1 Marks Question

Question 1011 Mark

In the ring test of $\text{NO}_3^-$ ion, $Fe^{2+}$ ion reduces nitrate ion to nitric oxide, which combines with $Fe^{2+}$ (aq) ion to form brown complex. Write the reactions involved in the formation of brown ring.

Answer

$\text{NO}_3^-+3\text{Fe}^{2+}+4\text{H}^+\xrightarrow{\ \ \ \ \ \ \ \ \ \ }\text{NO}+3\text{Fe}^{3+}+2\text{H}_2\text{O}$
$[\text{Fe}(\text{H}_2\text{O})_6]^{2+}+\text{NO}\xrightarrow{\ \ \ \ \ \ \ \ \ }[\text{Fe}(\text{H}_2\text{O})_5(\text{NO})]^{2+}+\text{H}_2\text{O}\\\ ^{(\text{brown complex})}$

View full question & answer→

Question 1021 Mark

With what neutral molecule is $ClO^–$ isoelectronic? Is that molecule a Lewis base?

Answer

Isoelectronic can be define as the molecules which have same number of electron.
$CIO^–$ is isoelectronic with ClF.
The molecule is a Lewis base.

View full question & answer→

Question 1031 Mark

Write a balanced chemical equation for the reaction showing catalytic oxidation of $NH_3$ by atmospheric oxygen.

Answer

$4\text{NH}_3+5\text{O}_2\xrightarrow{\text{Pt gauze}}4\text{NO}+6\text{H}_2\text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ ^{(\text{from air})}$

View full question & answer→

Question 1041 Mark

Why does orthophosphoric acid exist as a syrupy liquid?

Answer

Orthophosphoric acid contains three O-H groups and hence undergoes extensive H-bonding.

View full question & answer→

Question 1051 Mark

Why does $PCl_3$ fume in moisture?

Answer

$PCl_3$ hydrolyses in the presence of moisture giving fumes of HCl.
$\text{PCl}_3+3\text{H}_2\text{O}\ \ \ \rightarrow \ \ \ \text{H}_3\text{PO}_3+3\text{HCl}$

View full question & answer→

Question 1061 Mark

Write a balanced equation for the hydrolytic reaction of $PCl_5$ in heavy water.

Answer

$\text{PCl}_5+\text{D}_2\text{O}\rightarrow\text{POCl}_3+2\text{DCl}_2$
$\text{POCl}_3+3\text{D}_2\text{O}\rightarrow\text{D}_3\text{PO}_4+3\text{DCl}$
Therefore, the net reaction can be written as,
$\text{PCl}_5+4\text{D}_2\text{O}\rightarrow\text{D}_3\text{PO}_4+5\text{DCl}$

View full question & answer→

Question 1071 Mark

What are the oxidation states of phosphorus in the following:
$PCl_3$

Answer

$PCl_3$
Oxidation state of chlorine is $-3$
thus
$P+(-3) = 0$
$P = 3$
Here oxidation state is $+3.$

View full question & answer→

Question 1081 Mark

In trimethylamine, the nitrogen has a pyramidal geometry whereas in trisilylamine $N(SiH_3)_3$, it has a planar geometry.

Answer

$(CH_3)_3N$ is pyramidal due to sp^3 hybridisation and has a lone pair of electrons. $(SiH_3)_3N$ has $sp^2$ hybridisation because lone pair of nitrogen is donated to vacant d-orbital of Si.

View full question & answer→

Chemistry 1 Marks Question