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Science M.C.Q

Acids, Bases and Salts · Maharashtra Board STD 10 (MSBSHSE - Semi English Medium). 39 questions.

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M.C.Q

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39 questions · auto-graded multiple-choice test.

MCQ 11 Mark
The property which is not shown by acids is:
  • A
    They have sour taste.
  • ✓
    They feel soapy.
  • C
    They turn litmus red.
  • D
    Their $pH$ is less than seven.
Answer
Correct option: B.
They feel soapy.
Acids have a sour taste, they turn blue litmus paper red and their $pH$ is less than seven. But they do not feel soapy.
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MCQ 21 Mark
The colour of methyl orange indicator in a solution is yellow. The $pH$ of this solution is likely to be:
  • A
    $7$
  • B
    Less than $7$
  • C
    $0$
  • ✓
    More than $7$
Answer
Correct option: D.
More than $7$
Basic or alkaline solutions turn a methyl orange indicator yellow. Thus, the $pH$ of the solution is likely to be more than $7.$
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MCQ 31 Mark
The products of chlor$-$alkali process are:
  • A
    $\ce{NaCl, Cl_2}$ and $\ce{H_2}$
  • ✓
    $\ce{H_2, Cl_2}$ and $\ce{NaOH}$
  • C
    $\ce{Cl_2, Na_2CO_3}$ and $\ce{H_2O}$
  • D
    $\ce{NaOH, Cl_2}$ and $\ce{HCl}$
Answer
Correct option: B.
$\ce{H_2, Cl_2}$ and $\ce{NaOH}$
The process of electrolysis of sodium chloride solution is called the chlor$-$alkali process because of the products formed, i.e., $\ce{H_2, Cl_2}$ and $\ce{NaOH.}$ 'Chlor' stands for chlorine and 'alkali' for sodium hydroxide $\ce{(NaOH)}.$
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MCQ 41 Mark
A solution reacts with marble chips to produce a gas which turns lime water milky. The solution contains:
  • A
    $Na_2SO_4$
  • B
    $CaSO_4$
  • C
    $H_2SO_4$
  • ✓
    $K_2SO_4$
Answer
Correct option: D.
$K_2SO_4$
Marble chips contain calcium carbonate $\left( CaCO _3\right)$, which reacts with sulphuric acid $\left( H _2 SO _4\right)$ to form carbon dioxide gas $\left( CO _2\right)$.
Carbon dioxide gas, when passed through lime water $\left[ Ca ( OH )_2\right]$, turns it milky.
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MCQ 51 Mark
The salt which will give a neutral solution on dissolving in water will be:
  • A
    $CH_3COONa$
  • B
    $NH_4Cl$
  • ✓
    $KCl$
  • D
    $Na_2CO_3$
Answer
Correct option: C.
$KCl$
$KCl$ is formed from a strong acid, hydrochloric acid $(HCl)$, and a strong base, potassium hydroxide $(KOH)$. On dissolving in water, $KCl$ hydrolyses to form equal amounts of $H^+$ and $OH^-$ ions. This is why an aqueous solution of $KCl$ is neutral with a pH of almost $7$.
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MCQ 61 Mark
Which of the following types of medicine is used for treating indigestion caused by over$-$eating?
  • A
    Antibiotic.
  • B
    Analgesic.
  • ✓
    Antacid.
  • D
    Antiseptic.
Answer
Correct option: C.
Antacid.
Indigestion is caused by the formation of excess acid in the stomach. An antacid is a medicine that is generally a base or a basic salt that neutralises acidity in the stomach.
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MCQ 71 Mark
It has been found that rubbing vinegar on the stung area of the skin of a person gives him relief. The person has been stung by:
  • ✓
    Wasp
  • B
    Ant
  • C
    Honey bee.
  • D
    Nettle leaf hair.
Answer
Correct option: A.
Wasp
When a wasp stings a person, it injects an alkaline solution into the person's skin. This causes high irritation and pain. Applying a weak acid, such as vinegar, to the wound neutralises the alkaline solution and soothes the pain.
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MCQ 81 Mark
The aqueous solution of one of the following salts will turn red litmus to blue. This salt is:
  • A
    Potassium sulphate.
  • B
    Sodium sulphate.
  • C
    Odium chloride.
  • ✓
    Potassium carbonate.
Answer
Correct option: D.
Potassium carbonate.
Potassium carbonate $\left( K _2 CO _3\right)$ is formed from a weak acid, carbonic acid $\left( H _2 CO _3\right)$, and a strong base, potassium hydroxide $( KOH )$. On hydrolysis, $K _2 CO _3$ forms more $OH ^{-}$ions than $H ^{+}$ions.
Thus, it is basic and therefore turns red litmus blue.
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MCQ 91 Mark
The daffodil plants grow best in a soil having a $pH$ range of $6.0$ to $6.5.$ If the soil in a garden has a $pH$ of $4.5,$ which substance needs to be added to the soil in order to grow daffodils?
  • A
    Salt.
  • ✓
    Lime.
  • C
    Sand.
  • D
    Compost.
Answer
Correct option: B.
Lime.
If the $pH$ of the soil is $4.5,$ then it is highly acidic. Thus, soil should be treated with a base, such as quick lime $($calcium oxide$)$ or slaked lime $($calcium hydroxide$).$ These bases react with the excess acid present in the soil and neutralises it. Thus, the $pH$ of the soil is increased, making it suitable for growing daffodils.
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MCQ 101 Mark
The aqueous solution of one of the following salts will turn phenolphthalein indicator pink. This salt is:
  • A
    $KCl$
  • B
    $K_2SO_4$
  • ✓
    $K_2CO_3$
  • D
    $KNO_3$
Answer
Correct option: C.
$K_2CO_3$
$K_2CO_3$ is formed from a weak acid, carbonic acid $(H_2CO_3)$, and a strong base, potassium hydroxide $(KOH)$. On hydrolysis, $K_2CO_3$ forms more $OH^-$ ions than $H^+$ ions, and thus, it is basic. As the aqueous solution of the salt is basic, it turns a phenolphthalein indicator pink.
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MCQ 111 Mark
Fresh milk has a $pH$ of $6.$ When milk changes into curd, the $pH$ value will:
  • A
    Become $7$
  • ✓
    Become less than $6$
  • C
    Become more than $7$
  • D
    Remain unchanged.
Answer
Correct option: B.
Become less than $6$
When fresh milk changes into curd, its acidity increases and it turns sour Therefore, the $pH$ of fresh milk becomes less than $6$ when milk changes into curd.
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MCQ 121 Mark
The indicator which produces a pink colour in an alkaline solution is:
  • A
    Methyl orange.
  • B
    Turmeric paper.
  • ✓
    Phenolphthalein.
  • D
    Litmus paper.
Answer
Correct option: C.
Phenolphthalein.
Phenolphthalein produces a pink colour in an alkali solution.
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MCQ 131 Mark
Which of the following is treated with chlorine to obtain bleaching powder?
  • A
    $CaSO_4$
  • ✓
    $Ca(OH)_2$
  • C
    $Mg(OH)_2$
  • D
    $KOH$
Answer
Correct option: B.
$Ca(OH)_2$
Bleaching powder $(CaOCl_2)$ is formed by passing chlorine gas over slaked lime $[Ca(OH)_2]$.
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MCQ 141 Mark
A salt is dissolved in water and the $pH$ of this salt solution is measured with a universal indicator paper. If the $pH$ of solution is less than $7$, the salt is most likely to be:
  • A
    $CH_3COONa$
  • B
    $Na_2CO_3$
  • C
    $KCl$
  • ✓
    $NH_4Cl$
Answer
Correct option: D.
$NH_4Cl$
$NH_4Cl$ is formed from a weak base, ammonium hydroxide $(NH_4OH),$ and a strong acid, hydrochloric acid $(HCl)$. On hydrolysis, $NH_4Cl$ forms more $H^+$ ions than $OH^-$ ions. Thus, it is acidic, with a pH less than $7$.
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MCQ 151 Mark
The discomfort caused by indigestion due to overeating can be cured by taking:
  • A
    Vinegar.
  • B
    Lemon juice.
  • ✓
    Baking soda.
  • D
    Caustic soda.
Answer
Correct option: C.
Baking soda.
Baking soda, being a base, neutralises the excess acid formed in the stomach and cures the discomfort caused by indigestion.
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MCQ 161 Mark
Bee stings can be treated with:
  • A
    Vinegar.
  • ✓
    Sodium hydrogencarbonate.
  • C
    Potassium hydroxide.
  • D
    Lemon juice.
Answer
Correct option: B.
Sodium hydrogencarbonate.
When a bee stings a person, it injects an acidic solution into the person’s skin, which causes severe pain and an itching sensation. Applying a baking soda solution $($sodium hydrogen carbonate solution, which is a base$)$ soothes the pain by neutralising the acid.
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MCQ 171 Mark
A solution turns blue litmus red. Its $pH$ is likely to be:
  • A
    $7$
  • ✓
    $5$
  • C
    $8$
  • D
    $14$
Answer
Correct option: B.
$5$
An acidic solution turns blue litmus red. On the $pH$ scale, acids have values less than $7,$ whereas bases have values greater than $7.$ Solutions with $pH$ equal to $7$ are neutral in nature. Therefore, the $pH$ of the given solution is likely to be $5.$
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MCQ 181 Mark
The salt which will give an acidic solution on dissolving in water is:
  • A
    $KCl$
  • ✓
    $NH_4Cl$
  • C
    $Na_2CO$
  • D
    $CH_3COONa$
Answer
Correct option: B.
$NH_4Cl$
$NH_4Cl$ is formed with a weak base, ammonium hydroxide $(NH_4OH)$, and a strong acid, hydrochloric acid $(HCl)$. On dissolving in water, $NH_4Cl$ hydrolyses to form more $H^+$ ions than $OH$ ions. Thus, it is acidic with a pH less than $7$.
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MCQ 191 Mark
The number of molecules of water of crystallisation present in washing soda crystals is:
  • A
    Five.
  • B
    Two.
  • ✓
    Ten.
  • D
    Seven.
Answer
Correct option: C.
Ten.
The chemical formula of washing soda is $\ce{Na_2CO_3.10H_2O}$. The water molecules that form part of the structure of a salt are called its water of crystallisation.
Hence, the number of molecules of water of crystallisation present in washing soda crystals is $10$.
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MCQ 201 Mark
A solution reacts with zinc granules to give a gas which burns with a 'pop' sound. The solution contains:
  • A
    $Mg(OH)_2$
  • B
    $Na_2CO_3$
  • C
    $NaCl$
  • ✓
    $HCl$
Answer
Correct option: D.
$HCl$
Zinc granules react with $HCl$ to give hydrogen gas, which burns with a ‘pop’ sound.
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MCQ 211 Mark
A salt whose aqueous solution will have a $pH$ of more than $7$ will be:
  • ✓
    $K_2CO_3$
  • B
    $K_2SO_4$
  • C
    $NaCl$
  • D
    $NH_4Cl$
Answer
Correct option: A.
$K_2CO_3$
$K_2CO_3$ is formed from a weak acid, carbonic acid $(H_2CO_3)$, and a strong base, potassium hydroxide $(KOH)$. On hydrolysis, $K_2CO_3$ forms more $OH^-$ ions than $H^+$ ions. Thus, it is basic, with a $pH$ more than $7$.
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MCQ 221 Mark
The salt whose aqueous solution will turn blue litmus to red is:
  • ✓
    Ammonium sulphate.
  • B
    Sodium acetate.
  • C
    Sodium chloride.
  • D
    Potassium carbonate.
Answer
Correct option: A.
Ammonium sulphate.
Ammonium sulphate $[(NH_4)_2SO_4]$ is formed from a weak base, ammonium hydroxide $(NH_4OH)$, and a strong acid, sulphuric acid $(H_2SO_4)$.
On dissolving in water, $(NH_4)_2SO_4$ hydrolyses to form more $H^+$ ions than $OH^-$ ions.
​​​​​​​ As the aqueous solution of the salt $(NH_4)_2SO_4$​​​​​​​ is acidic, it turns blue litmus red.
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MCQ 231 Mark
The salt whose aqueous solution will have no effect on either red litmus or blue litmus is:
  • ✓
    Potassium sulphate.
  • B
    Sodium carbonate.
  • C
    Ammonium sulphate.
  • D
    Sodium acetate.
Answer
Correct option: A.
Potassium sulphate.
Potassium sulphate $(K_2SO_4)$ is formed from a strong acid, sulphuric acid $(H_2SO_4)$, and a strong base, potassium hydroxide $(KOH)$. On dissolving in water, $K_2SO_4$ hydrolyses to form equal amounts of $H^+$ and $OH^-$​​​​​​​ ions. As the salt solution of $K_2SO_4i$s neutral, it has no effect on red or blue litmus paper.
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MCQ 241 Mark
Wasp sting contains:
  • A
    A sugar solution.
  • B
    An acidic liquid.
  • C
    A salt solution.
  • ✓
    An alkaline liquid.
Answer
Correct option: D.
An alkaline liquid.
A wasp sting injects an alkaline solution into the skin, which causes high irritation and pain.
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MCQ 251 Mark
The property which is common between vinegar and curd is that they:
  • A
    Have sweet taste.
  • B
    Have bitter taste.
  • C
    Are tasteless.
  • ✓
    Have sour taste.
Answer
Correct option: D.
Have sour taste.
Vinegar and curds are acidic. They both have a sour taste.
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MCQ 261 Mark
Plaster of Paris is prepared by heating one of the following to a temperature of $100^\circ C$. This is:
  • A
    $CaSO_3.2H_2O$
  • B
    $CaCl_2.2H_2O$
  • C
    $CaCO_3.2H_2O$
  • ✓
    $CaSO_4.2H_2O$
Answer
Correct option: D.
$CaSO_4.2H_2O$
When $CaSO _4 \cdot 2 H _2 O$ (gypsum) is heated to a temperature of $100^{\circ} C (373 K)$, it loses three$-$fourths of its water of crystallisation and forms plaster of Paris ( $\left.CaSO _4 \cdot 1 / 2 H _2 O \right)$.
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MCQ 271 Mark
One of the following does not inject an acidic liquid into the skin through its sting. This is:
  • A
    Honey bee.
  • B
    Ant.
  • ✓
    Wasp.
  • D
    Nettle leaf hair.
Answer
Correct option: C.
Wasp.
A honey bee, ant and a nettle leaf hair inject methanoic acid into the skin through their stings. But a wasp injects an alkaline solution into the skin through its sting.
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MCQ 281 Mark
The indicators which turn red in acid solution are:
  • A
    Turmeric and litmus.
  • B
    Phenolphthalein and methyl orange.
  • ✓
    Litmus and methyl orange.
  • D
    Phenolphthalein and litmus.
Answer
Correct option: C.
Litmus and methyl orange.
Litmus and methyl orange turn red in an acid solution.
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MCQ 291 Mark
One of the following salts will give an alkaline solution on dissolving in water. This is:
  • ✓
    $Na_2CO_3$
  • B
    $Na_2SO_4$
  • C
    $NaCl$
  • D
    $(NH_4)_2 SO_4$
Answer
Correct option: A.
$Na_2CO_3$
$Na _2 CO _3$ is formed from a weak acid, carbonic acid $\left( H _2 CO _3\right)$, and a strong base, sodium hydroxide $( NaOH )$. On dissolving in water, $Na _2 CO _3$ hydrolyses to form more $OH ^{-}$ions than $H ^{+}$ions. Therefore, its solution in water is basic, or alkaline, with a $pH$ more than $7$ .
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MCQ 301 Mark
The formula of baking soda is:
  • A
    $K_2CO_3$
  • B
    $KHCO_3$
  • ✓
    $NaHCO_3$
  • D
    $Na_2CO_3$
Answer
Correct option: C.
$NaHCO_3$
The chemical name of baking soda is sodium hydrogen carbonate, and its chemical formula is $NaHCO_3$​​​​​​​.
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MCQ 311 Mark
Bee sting contains:
  • ✓
    An acidic liquid.
  • B
    A salt solution.
  • C
    An alkaline liquid.
  • D
    An alcohol.
Answer
Correct option: A.
An acidic liquid.
A bee sting contains an acidic solution. The name of the acid is methanoic acid.
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MCQ 321 Mark
One of the following is a medicine for indigestion. This is:
  • A
    Sodium hydroxide.
  • B
    Manganese hydroxide.
  • ✓
    Magnesium hydroxide.
  • D
    Potassium hydroxide.
Answer
Correct option: C.
Magnesium hydroxide.
Magnesium hydroxide, which is a base, acts as an antacid. It neutralises excess acid present in the stomach and cures indigestion. Hence, it is used as a medicine.
 
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MCQ 331 Mark
$10\ mL$ of a solution of $\ce{NaOH}$ is found to be completely neutralised by $8\ mL$ of a given solution of $\ce{HCl}.$ If we take $20\ mL$ of the same solution of $\ce{NaOH},$ the amount of $\ce{HCl}$ solution $($the same solution as before$)$ required to neutralise it will be:
  • A
    $4\ mL$
  • B
    $8\ mL$
  • C
    $12\ mL$
  • ✓
    $16\ mL$
Answer
Correct option: D.
$16\ mL$
It is given that $10\ mL$ of a solution of $\ce{NaOH}$ is completely neutralised by $8\ mL$ of a solution of $\ce{HCl}.$ Hence, $20\ mL$ of the solution of $\ce{NaOH},$ which is double the amount taken earlier, will require double the solution of $\ce{HCl}$ taken earlier, i.e., $16\ mL,$ to be completely neutralised.
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MCQ 341 Mark
One of the following is not an organic acid. This is:
  • A
    Ethanoic acid.
  • B
    Formic acid.
  • C
    Citric acid.
  • ✓
    Carbonic acid.
Answer
Correct option: D.
Carbonic acid.
Carbonic acid $\ce{H_2CO_3}$ is formed when $\ce{CO_2}$ is dissolved in water. Hence, carbonic acid is an inorganic or mineral acid.
Ethanoic acid, formic acid and citric acid are found naturally.
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MCQ 351 Mark
A solution turns red litmus blue. Its $pH$ is likely to be:
  • A
    $1$
  • B
    $4$
  • C
    $5$
  • ✓
    $10$
Answer
Correct option: D.
$10$
A basic solution turns red litmus blue. On the $pH$ scale, bases have values greater than $7,$ whereas acids have values less than $7.$ Therefore, the $pH$ of the given solution is likely to be $10.$
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MCQ 361 Mark
The acid produced naturally in our stomach is:
  • A
    Acetic acid.
  • B
    Citric acid.
  • ✓
    Hydrochloric acid.
  • D
    Sulphuric acid.
Answer
Correct option: C.
Hydrochloric acid.
Our stomach produces dilute hydrochloric acid naturally. The acid that is produced, which has a $pH$ of around $1.4,$ does not damage our stomach. Rather, it helps in the digestion of food.
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MCQ 371 Mark
Wasp stings can be treated with:
  • A
    Baking soda.
  • ✓
    Vinegar.
  • C
    Washing soda.
  • D
    Milk of magnesia.
Answer
Correct option: B.
Vinegar.
When a wasp stings a person, it inserts an alkaline solution into the person's skin. This causes high irritation and pain. Applying a weak acid, such as vinegar, to the wound neutralises the alkaline solution and soothes the pain.
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MCQ 381 Mark
A solution turns phenolphthalein indicator pink. The most likely $pH$ of this solution will be:
  • A
    $6$
  • B
    $4$
  • ✓
    $9$
  • D
    $7$
Answer
Correct option: C.
$9$
Every substance with a $pH$ greater than $7$ is considered basic or alkaline. Basic or alkaline solutions turn phenolphthalein indicator pink. Thus, the $pH$ of the solution is most likely $9.$
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MCQ 391 Mark
Which of the following salts will give an aqueous solution having pH of almost $7$?
  • A
    $NH_4NO_3$
  • B
    $NH_4Cl$
  • C
    $CaCl_2$
  • ✓
    $KCl$
Answer
Correct option: D.
$KCl$
$KCl$ is formed from a strong acid, hydrochloric acid $(HCl)$, and a strong base, potassium hydroxide $(KOH)$. Thus, $KCl$, on hydrolysis, forms equal amounts of $H^+$ and $OH^-$ ions. This is why an aqueous solution of $KCl$ shows a $pH$ of almost $7$.
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