NEET Practice Questions (MCQs) with Answers & Solutions

(b) 

$$\begin{gathered} {\mathrm{Zn}}^{2+} + 2\mathrm{NaOH} \stackrel{ }{\to }2{\mathrm{Na}}^{+} + \mathrm{Zn}\left(\mathrm{OH}{)}_2 \\ \mathrm{Zn}\right(\mathrm{OH}{)}_2 + 2\mathrm{NaOH} \stackrel{ }{\to }{\mathrm{Na}}_2{\mathrm{ZnO}}_2 + 2{\mathrm{H}}_2\mathrm{O} \\ \mathrm{Thus}, {\mathrm{Na}}_2{\mathrm{ZnO}}_2 \mathrm{forms} 2 {\mathrm{Na}}^{+} \mathrm{and} {\left[{\mathrm{ZnO}}_2\right]}^{2-}\mathrm{ions}. \end{gathered}$$

(c) 

Brine is a solution of sodium chloride (NaCl) and water (H₂O). The process of electrolysis involves using an electric current to bring about a chemical change and make new chemicals. The electrolysis of brine is a large-scale process used to manufacture chlorine from salt

(c) $2{\mathrm{LiNO}}_3 \stackrel{ }{\to }{\mathrm{Li}}_2\mathrm{O} + 2{\mathrm{NO}}_2 + \frac{1}{2}{\mathrm{O}}_2$

(c) Soda lime is NaOH + CaO, used for decarboxylation in organic reactions.

(d) Glauber's salt is sodium sulphate decahydrate.

(c) The solublity of hydroxides increases down the group.

Solubilities of alkali metal hydroxides increase down the group
LiOH<KOH<RbOH<CsOH

(d) Al(OH)₃ is soluble in NaOH(aq) whereas Fe(OH)₃ is insoluble.

(a) All metals show metallic bonding involving oscillations of electrons in them and thus, are good conductor of heat and electricity.

(b) $$\begin{gathered} {\mathrm{ZnSO}}_4 + 2\mathrm{NaOH} \stackrel{ }{\to }\mathrm{Zn}(\mathrm{OH}{)}_2 + \mathrm{Na}2\mathrm{SO}4 \\ \mathrm{ppt}. \end{gathered}$$

$$\begin{gathered} \mathrm{Zn}(\mathrm{OH}{)}_2 + 2\mathrm{NaOH} \stackrel{ }{\to }{\mathrm{Na}}_2{\mathrm{ZnO}}_2 + 2{\mathrm{H}}_2\mathrm{O} \\ \mathrm{soluble} \end{gathered}$$

(a) Li₂CO₃ decomposes on heating;

                 ${\mathrm{Li}}_2{\mathrm{CO}}_3 \stackrel{ }{\to }{\mathrm{Li}}_2\mathrm{O} + {\mathrm{CO}}_2$