Question 11 Mark
For the following equilibrium, $\text{K}_{\text{c}}=6.3\times10^{14}\text{ at }1000\text{K}$
$\text{NO(g) + O}_3\text{(g)}\rightleftharpoons\text{NO}_2\text{(g) + O}_2\text{(g)}$
Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is $\text{K}_{\text{c}}$, for the reverse reaction?
AnswerFor the reverse reaction $\text{K}_{\text{c}}=\frac{1}{\text{K}_{\text{c}}}=\frac{1}{6.3\times10^{14}}=1.59\times10^{-15.}$
View full question & answer→Question 21 Mark
What will be the conjugate bases for the Brönsted acids: $\mathrm{HF}, \mathrm{H}_2 \mathrm{SO}_4$ and $\text{HCO}_3^-$?
AnswerThe table below lists the conjugate bases for the given Bronsted acids.
| $\text{Bronsted acid Conjugate base}$ |
| $\text{HF}$ |
$\text{F}^-$ |
| $\text{H}_2\text{SO}_4$ |
$\text{HSO}_4^-$ |
| $\text{HCO}_3^-$ |
$\text{CO}_3^{2-}$ |
View full question & answer→Question 31 Mark
Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
$\text{4NH}_3\text{ (g) + 5O}_2\text{ (g)}\rightleftharpoons\text{4NO}\text{ (g) + 6H}_2\text{O (g)}$
AnswerOnly those reactions will be affected by increasing the pressure in which the number of moles of the gaseous reactants and products are different ( $n_p \neq n_r$ ) (gaseous). With the exception of the reaction (1); all the reamaining five reactions will get affected by increasing the pressure. In general,
- The reaction will go to the left if $n_p>n_r$.
- The reaction will go to the right if $n_r>n_p$. Keeping this in mind,
Increase in pressure will favour backward reaction because $n_p(1)>n_r(0)$. View full question & answer→Question 41 Mark
Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:
Human muscle-fluid, 6.83
AnswerHuman muscle fluid 6.83:
$\text{pH}=6.83$
$\text{pH}=-\log\text{[H}^+]$
$\therefore\ 6.83=-\log[\text{H}^+]$
$[\text{H}^+]=1.48\times10^{-7}\text{M}$
View full question & answer→Question 51 Mark
Predict which of the following reaction will have appreciable concentration of reactants and products: $\text{Cl}_2\text{ (g)}+\text{2NO (g)}\rightleftharpoons2\text{NOCl (g) K}_\text{c}=3.7\times10^8$
AnswerFollowing conclusions can be drawn from the values of $\text{K}_{\text{c}}$.
Since the value of $\text{K}_{\text{c}}$ is quite large, this means that the molar concentration of the products is very large as compared to that of the reactants.
View full question & answer→Question 61 Mark
Describe the effect of:
removal of $\mathrm{CH}_3 \mathrm{OH}$ on the equilibrium of the reaction:
$2\text{H}_2\text{ (g) + CO (g)}\rightleftharpoons\text{CH}_3\text{OH (g)}$
AnswerOn removing $\mathrm{CH}_3 \mathrm{OH}$, the equilibrium will shift in the forward direction.
View full question & answer→Question 71 Mark
Predict if the solutions of the following salts are neutral, acidic or basic:
$\text{NH}_4\text{NO}_3$
Answer
| $\text{NH}_4\text{NO}_3$ |
$+$ |
$\text{H}_2\text{O}$ |
$\leftrightarrow$ |
$\text{NH}_4\text{OH}$ |
$+$ |
$\text{HNO}_3$ |
| |
|
|
|
$\text{Weak base}$ |
|
$\text{Strong acid}$ |
Therefore, it is an acidic solution. View full question & answer→Question 81 Mark
Describe the effect of:
addition of $\mathrm{CH}_3 \mathrm{OH}$ on the equilibrium of the reaction:
$2\text{H}_2\text{ (g) + CO (g)}\rightleftharpoons\text{CH}_3\text{OH (g)}$
AnswerOn addition of $\mathrm{CH}_3 \mathrm{OH}$, the equilibrium will shift in the backward direction.
View full question & answer→Question 91 Mark
Which of the followings are Lewis acids? $\mathrm{H}_2 \mathrm{O}, \mathrm{BF}_3, \mathrm{H}^{+}$, and $\text{NH}_4^+$
Answer$\mathrm{BF}_3, \mathrm{H}^{+}$ and $\text{NH}_4^+$ are Lewis acids because they can accept a lone pair of electrons.
View full question & answer→Question 101 Mark
Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:
Human stomach fluid, 1.2
AnswerHuman stomach fluid, 1.2:
$\text{pH}=1.2$
$1.2=-\log[\text{H}^+]$
$\therefore\ [\text{H}^+]=0.063$
View full question & answer→Question 111 Mark
Predict if the solutions of the following salts are neutral, acidic or basic:
NaCl
Answer
| $\text{NaCl}$ |
$+$ |
$\text{H}_2\text{O}$ |
$\leftrightarrow$ |
$\text{NaOH}$ |
$+$ |
$\text{HCl}$ |
| |
|
|
|
$\text{Strong base}$ |
|
$\text{Strong acid}$ |
Therefore, it is a neutral solution. View full question & answer→Question 121 Mark
At 473 K , equilibrium constant $\mathrm{K}_{\mathrm{c}}$ for decomposition of phosphorus pentachloride, $\mathrm{PCl}_5$ is $8.3 \times 10^{-3}$. If decomposition is depicted as,
$\mathrm{PCl}_5(\mathrm{~g}) \rightleftharpoons \mathrm{PCl}_3(\mathrm{~g})+\mathrm{Cl}_2(\mathrm{~g}) \Delta_{\mathrm{r}} \mathrm{H}^{\ominus}=124.0 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}$
write an expression for $\mathrm{K}_{\mathrm{c}}$ for the reaction.
Answer$\text{K}_\text{c}=\frac{[\text{PCl}_{3\text{(g)}}][\text{Cl}_{2\text{(g)}}]}{[\text{PCl}_{5\text{(g)}}]}$
View full question & answer→Question 131 Mark
Write the expression for the equilibrium constant, $\text{K}_{\text{c}}$ for each of the following reactions: $\text{2NOCl(g)}\rightleftharpoons\text{2NO (g) + Cl}_2\text{ (g)}$
Answer$\text{K}_{\text{c}}=\frac{[\text{NO(g)]}^2[\text{Cl}_2\text{(g)}]}{[\text{NOCl(g)}]^2}$
View full question & answer→Question 141 Mark
Predict if the solutions of the following salts are neutral, acidic or basic:
KF
Answer
| $\text{KF}$ |
$+$ |
$\text{H}_2\text{O}$ |
$\leftrightarrow$ |
$\text{KOH}$ |
$+$ |
$\text{HF}$ |
| |
|
|
|
$\text{Strong base}$ |
|
$\text{weak acid}$ |
Therefore, it is a basic solution. View full question & answer→Question 151 Mark
Predict which of the following reaction will have appreciable concentration of reactants and products: $\text{Cl}_2\text{ (g)}+\text{2NO}_2\text{ (g)}\rightleftharpoons2\text{NO}_2\text{Cl (g) K}_\text{c}=1.8$
AnswerFollowing conclusions can be drawn from the values of $\text{K}_{\text{c}}$. Since the value of $\text{K}_{\text{c}}$ is 1.8, this means that both the products and reactants have appreciable concentration.
View full question & answer→Question 161 Mark
Write the expression for the equilibrium constant, $\text{K}_{\text{c}}$ for each of the following reactions:
$\text{I}_2\text{(S)}+5\text{F}_2\rightleftharpoons2\text{IF}_5$
Answer$\text{K}_{\text{c}}=\frac{[\text{IF}_5\text{(l)}]^2}{[\text{l}_2\text{(S)}][\text{F}_2\text{(g)}]^5}$ $=\frac{[\text{IF}_5\text{(l)}]^2}{[\text{F}_2\text{(g})']^5}$
View full question & answer→Question 171 Mark
Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
$\text{COCl}_2\text{ (g)}\rightleftharpoons\text{CO (g) + Cl}_2\text{ (g)}$
AnswerOnly those reactions will be affected by increasing the pressure in which the number of moles of the gaseous reactants and products are different ( $n_p \neq n_r$ ) (gaseous). With the exception of the reaction (1); all the reamaining five reactions will get affected by increasing the pressure. In general,
- The reaction will go to the left if $n_p>n_p$.
- The reaction will go to the right if $n_r>n_p$. Keeping this in mind,
Increase in pressure will not affect equilibrium because $n_p=n_r=3$. View full question & answer→Question 181 Mark
Ethyl acetate is formed by the reaction between ethanol and acetic acid and the equilibrium is represented as:
$\text{CH}_3\text{COOH (1) + C}_2\text{H}_5\text{OH (1)}\rightleftharpoons\text{CH}_3\text{COOC}_2\text{H}_5 \text{ (1) + H}_2\text{O (1)}$
Write the concentration ratio (reaction quotient), $\text{Q}_{\text{c}}$, for this reaction (note: water is not in excess and is not a solvent in this reaction)
AnswerReaction quotient,$\text{Q}_{\text{c}}=\frac{[\text{CH}_3\text{COOC}_2\text{H}_5][\text{H}_2\text{O]}}{[\text{CH}_3\text{COOH][}\text{C}_2\text{H}_5\text{OH}] }$
View full question & answer→Question 191 Mark
Describe the effect of:
removal of CO
on the equilibrium of the reaction:
$2\text{H}_2\text{ (g) + CO (g)}\rightleftharpoons\text{CH}_3\text{OH (g)}$
AnswerOn removing CO, the equilibrium will shift in the backward direction.
View full question & answer→Question 201 Mark
Predict which of the following reaction will have appreciable concentration of reactants and products:
$\text{Cl}_2\text{ (g)}\rightleftharpoons2\text{Cl (g) K}_\text{c}=5\times10^{-39}$
AnswerFollowing conclusions can be drawn from the values of $\text{K}_{\text{c}}$.
Since the value of $\text{K}_{\text{c}}$ is very small, this means that the molar concentration of the products is very small as compared to that of the reactants.
View full question & answer→Question 211 Mark
Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
$\text{CaCO}_3\text{ (S)}\rightleftharpoons\text{CaO}\text{ (S) + CO}_2\text{ (g)}$
AnswerOnly those reactions will be affected by increasing the pressure in which the number of moles of the gaseous reactants and products are different ( $\mathrm{n}_{\mathrm{p}} \neq \mathrm{n}_{\mathrm{r}}$ ) (gaseous). With the exception of the reaction (1); all the reamaining five reactions will get affected by increasing the pressure. In general,
- The reaction will go to the left if $n_p>n_r$.
- The reaction will go to the right if $n_r>n_p$. Keeping this in mind,
Increase in pressure will favour backward reaction because $n_p(2)>n_r(1)$ View full question & answer→Question 221 Mark
Predict if the solutions of the following salts are neutral, acidic or basic:
$\text{NaNO}_2$
Answer
| $\text{NaNO}_2$ |
$+$ |
$\text{H}_2\text{O}$ |
$\leftrightarrow$ |
$\text{Na}\text{OH}$ |
$+$ |
$\text{HNO}_2$ |
| |
|
|
|
$\text{Strong base}$ |
|
$\text{weak acid}$ |
Therefore, it is a basic solution. View full question & answer→Question 231 Mark
Predict if the solutions of the following salts are neutral, acidic or basic:
$\text{KBr}$
Answer
| $\text{KBr}$ |
$+$ |
$\text{H}_2\text{O}$ |
$\leftrightarrow$ |
$\text{KOH}$ |
$+$ |
$\text{HBr}$ |
| |
|
|
|
$\text{Strong base}$ |
|
$\text{Strong acid}$ |
Therefore, it is a neutral solution. View full question & answer→Question 241 Mark
Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?
$\text{CaO}\text{ (S) + }\text{CO}_2\text{ (g)}\rightleftharpoons\text{CaCO}_3\text{ (S)}$
AnswerThe number of moles of reaction products will decrease.
View full question & answer→Question 251 Mark
Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
$\text{CO}_2\text{ (g) + C}\text{ (S)}\rightleftharpoons\text{2CO}\text{ (g)}$
AnswerOnly those reactions will be affected by increasing the pressure in which the number of moles of the gaseous reactants and products are different ( $n_p \neq n_r$ ) (gaseous). With the exception of the reaction (1); all the reamaining five reactions will get affected by increasing the pressure. In general,
- The reaction will go to the left if $n_p>n_r$.
- The reaction will go to the right if $n_r>n_p$. Keeping this in mind,
Increase in pressure will favour backward reaction because $n_p(10)>n_r(9)$ View full question & answer→Question 261 Mark
Describe the effect of:
addition of $\text{H}_2$ on the equilibrium of the reaction:
$2\text{H}_2\text{ (g) + CO (g)}\rightleftharpoons\text{CH}_3\text{OH (g)}$
AnswerAccording to Le Chatelier’s principle, on addition of $\text{H}_2$, the equilibrium of the given reaction will shift in the forward direction.
View full question & answer→Question 271 Mark
At 473 K , equilibrium constant $\mathrm{K}_{\mathrm{c}}$ for decomposition of phosphorus pentachloride, $\mathrm{PCl}_5$ is $8.3 \times 10^{-3}$. If decomposition is depicted as,
$\text{PCl}_5\text{ (g)}\rightleftharpoons\text{PCl}_3\text{ (g) + Cl}_2\text{ (g)}\ \Delta_\text{r}\text{H}^\ominus=124.0\text{ kJ mol}^{-1}$
what would be the effect on Kc if
- more PCl5 is added
- pressure is increased
- the temperature is increased?
Answer$\text{PCl}_{5\text{(g)}}\rightleftharpoons\text{PCl}_{3\text{(g)}}+\text{Cl}_{2\text{(g)}}$
- If more $\text{PCl}_5$ is added, then $\text{Q}_\text{c}$ becomes less than $\text{K}_{\text{c}'}$ the reaction will shift in the forward direction.
- If the pressure is increased, the reaction will shift towards backward direction as it contains less number of gaseous species. $\text{K}_\text{c}$ remains constant.
- As the reaction is endothermic, the increase in temperature will favour the forward reaction. More $\text{PCl}_5$ will dissociate to form $\text{PCl}_3$ and $\text{Cl}_2.$ $\text{K}_\text{c}$ increases.
View full question & answer→Question 281 Mark
Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
$\text{2H}_2\text{ (g) + CO}\text{ (g)}\rightleftharpoons\text{CH}_3\text{OH (g)}$
AnswerOnly those reactions will be affected by increasing the pressure in which the number of moles of the gaseous reactants and products are different ( $n_p \neq n_r$ ) (gaseous). With the exception of the reaction (1); all the reamaining five reactions will get affected by increasing the pressure. In general,
- The reaction will go to the left if $n_p>n_r$.
- The reaction will go to the right if $n_r>n_p$. Keeping this in mind,
Increase in pressure will favour forward reaction because $n_p(1)<n_r(2)$ View full question & answer→Question 291 Mark
At 473 K , equilibrium constant $\mathrm{K}_{\mathrm{c}}$ for decomposition of phosphorus pentachloride, $\mathrm{PCl}_5$ is $8.3 \times 10^{-3}$. If decomposition is depicted as,
$\mathrm{PCl}_5(\mathrm{~g}) \rightleftharpoons \mathrm{PCl}_3(\mathrm{~g})+\mathrm{Cl}_2(\mathrm{~g}) \Delta_{\mathrm{r}} \mathrm{H}^{\ominus}=124.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$
what is the value of $\mathrm{K}_{\mathrm{c}}$ for the reverse reaction at the same temperature?
Answer$\text{PCl}_{3\text{(g)}}+\text{Cl}_{2\text{(g)}}\rightleftharpoons\text{PCl}_{5\text{(g)}}$
$\therefore\ \text{K}'_\text{c}=\frac{[\text{PCl}_{5\text{(g)}}]}{[\text{PCl}_{3\text{(g)}}][\text{Cl}_{2\text{(g)}}]}=\frac{1}{8.3\times10^{-3}}=120.48$
View full question & answer→Question 301 Mark
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
What is the initial effect of the change on vapour pressure?
AnswerOn increasing the volume of the container, the vapour pressure will initially decrease because the same amount of vapours are now distributed over a larger space.
View full question & answer→Question 311 Mark
Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?
$\text{3Fe}\text{ (S) + }\text{4H}_2\text{O (g)}\rightleftharpoons\text{Fe}_3\text{O}_4\text{ (S) + 4H}_2\text{ (g)}$
AnswerThe number of moles of reaction products remains the same.
View full question & answer→Question 321 Mark
Write the expression for the equilibrium constant, $\text{K}_{\text{c}}$ for each of the following reactions:$\text{Fe}^{3+}\text{(aq)}+3\text{OH}^-\text{(aq)}\rightleftharpoons\text{Fe(OH})_3\text{(S)}$
Answer$\text{K}_{\text{c}}=\frac{[\text{Fe(OH})_3\text{(S)]}}{[\text{Fe}^{3+}\text{(aq)}][\text{OH}^-\text{(aq)}]^3}$
$=\frac{1}{[\text{Fe}^{3+}\text{(aq)}][\text{OH}^-\text{(aq)}]^3}$
View full question & answer→Question 331 Mark
Which of the following reactions will get affected by increasing the pressure? Also, mention whether change will cause the reaction to go into forward or backward direction.
$\text{CH}_4\text{ (g) + 2S}_2\text{ (g)}\rightleftharpoons\text{CS}_2\text{ (g) + 2H}_2\text{S}\text{ (g)}$
AnswerOnly those reactions will be affected by increasing the pressure in which the number of moles of the gaseous reactants and products are different ( $n_p \neq n_r$ ) (gaseous). With the exception of the reaction (1); all the reamaining five reactions will get affected by increasing the pressure. In general,
- The reaction will go to the left if $n_p>n_r$.
- The reaction will go to the right if $n_r>n_p$. Keeping this in mind,
Increase in pressure will favour backward reaction because $n_p(2)>n_r(1)$ View full question & answer→Question 341 Mark
Write the conjugate acids for the following Brönsted bases: $\text{NH}_2^-$, $\text{NH}_3$ and $\text{HCOO}^-$.
AnswerThe table below lists the conjugate acids for the given Bronsted bases.
| $\text{Bronsted base Conjugate acid}$ |
| $\text{NH}_2^-$ |
$\text{NH}_3$ |
| $\text{NH}_3$ |
$\text{NH}_4^+$ |
| $\text{HCOO}^-$ |
$\text{HCOOH}$ |
View full question & answer→Question 351 Mark
Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:
Human saliva, 6.4.
AnswerHuman saliva, 6.4:
$\text{pH}=6.4$
$6.4=-\log[\text{H}^+]$
$[\text{H}^+]=3.98\times10^{-7}$
View full question & answer→Question 361 Mark
Write the expression for the equilibrium constant, $\text{K}_{\text{c}}$ for each of the following reactions: $\text{CH}_3\text{COOC}_2\text{H}_5\text{(aq)}+\text{H}_2\text{O(l)}\rightleftharpoons\text{CH}_3\text{COOH(aq)+}\text{C}_2\text{H}_5\text{OH(aq)}$
Answer$\text{K}_{\text{c}}=\frac{[\text{CH}_3\text{COOH(aq)]}[\text{C}_2\text{H}_5\text{OH(aq)}]}{[\text{CH}_3\text{COOC}_2\text{H}_5\text{(aq)}][\text{H}_2\text{O(l)}]}$
$=\frac{[\text{CH}_3\text{COOH(aq)]}[\text{C}_2\text{H}_5\text{OH(aq)}]}{[\text{CH}_3\text{COOC}_2\text{H}_5\text{(aq)}]}$
View full question & answer→Question 371 Mark
Write the expression for the equilibrium constant, $\text{K}_{\text{c}}$ for each of the following reactions: $\text{2Cu(NO}_3)_2\rightleftharpoons\text{2CuO (s) + 4NO}_2\text{ (g) + O}_2\text{ (g)}$
Answer$\text{K}_{\text{c}}=\frac{[\text{CuO(g)]}^2[\text{NO}_2\text{(g)}]^4[\text{O}_2\text{(g)]}}{[\text{Cu(NO}_3)_2\text{}\text{(s)}]^2}$
$=[\text{NO}_2\text{(g)}]^4[\text{O}_2\text{(g)}]$
View full question & answer→Question 381 Mark
The equilibrium constant expression for a gas reaction is,
$\text{K}_{\text{c}}=\frac{[\text{NH}_3]^4[\text{O}_2]^5}{[\text{NO}]^4[\text{H}_2\text{O}]^6}$
Write the balanced chemical equation corresponding to this expression.
AnswerBalanced chemical equation for the reaction is 4
$4\text{NO (g) + 6H}_2\text{O (g)}\rightleftharpoons4\text{NH}_3\text{ (g) + 5O}_2\text{ (g)}$
View full question & answer→Question 391 Mark
Calculate the hydrogen ion concentration in the following biological fluids whose pH are given below:
Human blood, 7.38
AnswerHuman blood, 7.38:
$\text{pH}=7.38=-\log[\text{H}^+]$
$\therefore\ [\text{H}^+]=4.17\times10^{-8}\text{M}$
View full question & answer→Question 401 Mark
What is Kc for the following equilibrium when the equilibrium concentration of each substance is:
${\left[\mathrm{SO}_2\right]=0.60 \mathrm{M},\left[\mathrm{O}_2\right]=0.82 \mathrm{M} \text { and }\left[\mathrm{SO}_3\right]=1.90 \mathrm{M} ?}$
$2 \mathrm{SO}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{SO}_{3(\mathrm{~g})}$
Answer$2 \mathrm{SO}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})} \rightleftharpoons 2 \mathrm{SO}_{3(\mathrm{~g})}$
Applying law of chemical equilibrium.
View full question & answer→Question 411 Mark
Predict if the solutions of the following salts are neutral, acidic or basic:
NaCN
Answer
| $\text{NaCN}$ |
$+$ |
$\text{H}_2\text{O}$ |
$\leftrightarrow$ |
$\text{HCN}$ |
$+$ |
$\text{NaOH}$ |
| |
|
|
|
$\text{Weak acid}$ |
|
$\text{Strong base}$ |
Therefore, it is a basic solution. View full question & answer→Question 421 Mark
Under what conditions is a substance precipitated from its solution?
AnswerPrecipitation takes place, when ionic product exceeds the solubility product.
View full question & answer→Question 431 Mark
Write expression of $\text{K}_{\text{p}}$ for the reaction:
$\text{N}_2\text{O(g)}\rightleftharpoons2\text{NO}_2(\text{g})$
Answer$\text{K}_{\text{p}}=\frac{(\text{P}_{\text{NO}_2})^2}{(\text{P}_{\text{N}_2\text{O}_4})}$
View full question & answer→Question 441 Mark
Why is solubility of AgI in NaI in less than that of pure water?
AnswerIt is due to common ion effect. $\mathrm{I}^{-}$will combine with $\mathrm{Ag}^{+}$to from AgI , therefore solubility of AgI will decrease.
$\text{A}_2\text{B}\rightleftharpoons2\text{A}^++\text{B}^{2-}\\'\text{s}'\ \ \ \ \ \ \ \ \ \ \ \text{2s}\ \ \ \ \ \ \ \ '\text{s}'$
$\text{K}_{\text{sp}}=[\text{A}^+]^2[\text{B}^{2-}]$
$32\times10^{-9}=4\text{s}^3$
$32\times10^{-9}=4\text{s}^{3}$
$\text{s}^3=8\times10^{-9}$
$\text{s}=2\times10^{-3}\text{mol L}^{-1}$
$[\because3\sqrt{8}=2]\text{ and }(10^{-9})\frac{1}{3}=10^{-3}$
View full question & answer→Question 451 Mark
For Tribasic acid $K_{a 1}>K_{a 2}>K_{a 3}$ what will happen to the acid strength of polyprotic acids if protons are lost?
AnswerAcid strength will decrease because $K_{a 2}$, is less than $K_{a 1}$ and $K_{a 3}$ is less than $K_{a 2}$
View full question & answer→Question 461 Mark
Which of the following is weakest acid?
$\text{HClO}_4,\text{HClO}_3,\text{HCl}_2,\text{HClO}$
Answer$\mathrm{HCl}_4 \mathrm{O}$ is weakest acid because Cl is in +1 oxidation state, i.e., lowest oxidation state.
View full question & answer→Question 471 Mark
Write $\text{K}_{\text{p}}$ in terms of $\text{K}_{\text{c}}$ for the following chemical reaction:
$2\text{SO}_2(\text{g})+\text{O}_2(\text{g})\rightleftharpoons2\text{SO}_3\text{(g)}$
Answer$\text{K}_{\text{p}}=\text{K}_{\text{c}}(\text{RT}^{\Delta\text{n}})$
$\Delta\text{n}=2-3=-1$
$\text{K}_{\text{c}}(\text{RT})^{-1}$
View full question & answer→Question 481 Mark
Is it possible to get precipitate of $\mathrm{Fe}(\mathrm{OH})_2$ at $\mathrm{pH}=2$ ? Give reason.
AnswerNo, Because $\mathrm{Fe}(\mathrm{OH})_3$ will dissolve in strongly acidic medium.
View full question & answer→Question 491 Mark
Which of the following is not Lewis base $\mathrm{Ag}^{+}, \mathrm{H}_2 \mathrm{O}, \mathrm{CN}^{-}, \mathrm{NH}_3$.
Answer$\mathrm{Ag}^{+}$, It is Lewis acid because it is positively charged and can accept electrons.
View full question & answer→Question 501 Mark
What is the effect of temperature on solubility product ($\text{K}_{\text{sp}}$)?
Answer$\text{K}_{\text{sp}}$ increases with increase in temperature because solubility increases.
View full question & answer→Question 511 Mark
Why is Lewis concept more useful than Bronsted Lowry concept?
AnswerLewis concept includes some of compounds like $\mathrm{BF}_3, \mathrm{BCl}_3, \mathrm{AlCl}_3$ as acids which Bronsted Lowry concept does not.
View full question & answer→Question 521 Mark
Is it possible to get precipitate of Is it possible to get precipitate of $\mathrm{Fe}(\mathrm{OH})_3$ at $\mathrm{pH}=2$ ? Give reason.? Give reason.
AnswerNo, because $\mathrm{Fe}(\mathrm{OH})_3$ will dissolve in strongly acidic medium.
View full question & answer→Question 531 Mark
Why pH of our blood remains constant at 7.4 through we quite often eat spicy food?
AnswerBlood contains basic buffer which keep its pH constant.
View full question & answer→Question 541 Mark
Write the expression for the equilibrium constant ($\text{K}_{\text{c}}$) for the reaction:
$\text{CH}_3\text{COOC}_2\text{H}_5(\text{aq})+\text{H}_2\text{O(l)}\\\rightleftharpoons\text{CH}_3\text{COOH}
(\text{aq})+\text{C}_2\text{H}_5\text{OH}(\text{aq})$
Answer$\text{K}_{\text{c}}=\frac{[\text{CH}_3\text{COOH}][\text{C}_2\text{H}_5\text{OH}]}{[\text{CH}_3\text{COOC}_2\text{H}_2\text{H}_5][\text{H}_2\text{O}]}$
View full question & answer→Question 551 Mark
Which of the following is strongest Lewis acid? $\text{CCl}_4,\text{AlCl}_3,\text{NCl}_3,\text{OCl}_2$
Answer$\text{AlCl}_3$ is strongest Lewis acid because its octet is not complete.
View full question & answer→Question 561 Mark
Write the equilibrium constant expression for following reaction:
$2\text{NOCl}(\text{g})\rightleftharpoons2\text{NO(g)}+\text{Cl}_2(\text{g})$
Answer$\text{K}=\frac{[\text{NO}^2][\text{Cl}_2]}{[\text{NOCl}^2]}$
View full question & answer→Question 571 Mark
$\text{SO}_3^{2-}$ is Bronsted base or acid and why?
Answer$\text{SO}_3^{2-}$ is Bronsted base because it can accept $\text{H}^+$.
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What is the conjugate base of $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$?
Answer$\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{OH}\right]^{2+}$ is conjugate base of $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$.
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Fizz is observed when soda water bottle is opened. Why?
AnswerPressure is decreased, solubility of $\text{CO}_2$ in water decreases, $\text{CO}_2$ escapes from cold drink bottle.
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Which of the following is strongest conjugate base? $\text{CH}_3^-,\text{NH}^-_2,\text{OH}^-,\text{F}^-$
Answer$\text{CH}_4^-$ is strongest conjugate base because $\text{CH}_4$ is weakest acid, i.e., cannot donate $\text{H}^+$ easily.
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Write expression of $\text{K}_{\text{c}}$ for reaction:
$\text{N}_2(\text{g})+3\text{H}_2(\text{g})\rightleftharpoons2\text{NH}_3(\text{g})$
Give units of K.
Answer$\text{K}=\frac{[\text{NH}_3]^2}{[\text{N}_2][\text{H}_2]^3}$
$=\frac{(\text{mol L}^{-1})^2}{(\text{mol}^{-1})(\text{mol L}^{-1})^3}=\text{L}^2\text{mol}^{-2}$
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How does common ion affect the solubility of electrolyte?
AnswerSolubility of electroyte decreases due to common ion effect.
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Write the conjugate acid for the Bronsted base $\text{C}_6\text{H}_5\text{OH},\text{H}_2\text{O}$
Answer$\ \ \ \ \ \ \ \ \oplus{}\ \ \ \ \ \ \ \ \ \ \oplus{}\\\text{C}_6\text{H}_5\text{OH}_2,\text{H}_3\text{O}$
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Classify the following as Lewis acid or Lewis base: $\text{NH}_4^+\text{ and }\text{NH}_3$
Answer$\text{NH}^+_4$ Lewis acid, whereas $\text{NH}_3$ is Lewis base.
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What happens to ionic product of water if some acid is added to it?
AnswerIonic product will remain unchanged.
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If $Q_c<K_c$, in which direction reaction will proceed?
AnswerIf $Q_c<K_c$, the reaction will proceed in the direction of products.
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