Q11 / 160 · AP EAMCET 2018 (22 Apr Shift 2) · Chemistry
Identify the correct statements from the following.
(i) $\mathrm{Zn}$ reacts with dilute $\mathrm{HCl}$ and aqueous $\mathrm{NaOH}$ solution separately and liberates hydrogen.
(ii) Ti and Zr form interstitial hydrides.
iii) The viscosity of $\mathrm{H}_2 \mathrm{O}$ is more than the viscosity of $\mathrm{D}_2 \mathrm{O}$.
- A(i), (ii), (iii)
- B(i), (iii)
- Correct answerC(i), (ii)
- D(ii), (iii)
Solution
$$
\begin{aligned}
& \text { (i) } \mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \longrightarrow \\
& \mathrm{Zn}^{2+}(a q)+2 \mathrm{Cl}^{-}(a q)+\mathrm{H}_2(g) \\
&
\end{aligned}
$$
Zn comes into contact with $\mathrm{HCl}$ acid. It replaces the hydrogen from $\mathrm{HCl}$ molecule.
$$
\mathrm{Zn}(\mathrm{s})+2 \mathrm{HCl} \longrightarrow \mathrm{ZnCl}_2+\mathrm{H}_2
$$
(ii) Hydrides are classified into three categories, according to the nature of their bonding. Saline hydrides have a covalent bond, interstitial hydrides have a metallic bond and $d$-block elements make interstitial hydrides.
(iii) Viscosity of $\mathrm{H}_2 \mathrm{O}$ is more than the viscosity of $\mathrm{D}_2 \mathrm{O}$. This statement is wrong.
Hence, the correct answer is option: 'C'.