Chemistry MCQs for NEET — Practice Questions with Answers

CaBO₂ is calcium meta borate (Ca²⁺BO^-₂).

H₂O has the highest boiling point due to the presence of hydrogen bonding.

(b) Two different halogens may react to form interhalogen compounds as

XX' (ClF,BrF,BrCl,IF,ICl)   Linear

XX'₃ (ClF₃,BrF₃,IF₃,ICl₃) Bent T-shaped

XX'₅ (ClF₅,BrCl₅,IF₅)      Square-pyramidal

XX'₇ (IF₇)                     Pentagonal bipyramidal

(b) Key Idea Al³⁺shows maximum coordination number 6, thus it will form ${\mathrm{AF}}_6^{-3}$

AIF₃ forms K₃[AIF₆] when dissolved in HF in the presence of KF as shown below:

${\mathrm{AlF}}_3+ 3\mathrm{KF}\stackrel{ \mathrm{HF} }{\to }{\mathrm{K}}_3\left[{\mathrm{AlF}}_6\right]$

The reaction of CaF2 with H2SO4 does not involve any oxidation process. It is an acid-base reaction where HF is formed. The other reactions given involve the oxidation of Cu, S, and C by hot concentrated H2SO4 acting as an oxidizing agent.

The statement that SeF4 and CH4 have the same shape is incorrect. SeF4 has a see-saw shape (distorted tetrahedral), while CH4 has a tetrahedral shape. The other statements given are correct.

(d) Nitric acid acts as an oxidising agent while reacting with copper. When dil. HNO₃ reacts, reaction proceeds as:

$3\mathrm{Cu} + 8{\mathrm{HNO}}_3\left(\mathrm{dil}.\right) \stackrel{ }{\to }3\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2 +\hspace{0.17em}2\mathrm{NO} + {\mathrm{H}}_2\mathrm{O}$

and when conc. HNO₃ is used, reaction proceeds as

$\mathrm{Cu} + 4{\mathrm{HNO}}_3\left(\mathrm{conc}.\right) \stackrel{ }{\to }\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2 +\hspace{0.17em}2\mathrm{NO}2 + 2{\mathrm{H}}_2\mathrm{O}$

Species     Hybridisation     Bond angle
   NO₂               sp             120°
   NO_2^-              sp₂           115.4°
   NO_2⁺             sp(linear)   180°
   NO_3^-             sp₂             120°

So, No₂⁺ has maximum bond angle.