The effect of heating Boric acid at 370 K or above is -

1. Orthoboric acid changes to metaboric acid.

2. Metaboric acid changes to boric oxide.

3. Both '1' and '2'

4. Neither '1' nor '2'

The electron-deficient compound among the following is -

1. ${\mathrm{SiCl}}_4$

2. ${\mathrm{BCl}}_3$

3. ${\mathrm{PCl}}_3$

4. $\mathrm{ICl}$

The hybridization of carbon in (a) ${\mathrm{CO}}_3^{2-}$ (b) diamond (c) graphite is respectively:

1. ${\mathrm{sp}}^2$, ${\mathrm{sp}}^3$, ${\mathrm{sp}}^2$

2. ${\mathrm{sp}}^2$, ${\mathrm{sp}}^3$, $s{p}^3$

3. ${\mathrm{sp}}^3$, ${\mathrm{sp}}^3$, ${\mathrm{sp}}^2$

4. ${\mathrm{sp}}^3$, ${\mathrm{sp}}^2$, ${\mathrm{sp}}^3$

The B–F bond lengths in ${\mathrm{BF}}_3$ (130 pm) and $\mathrm{B}{{\mathrm{F}}_4}^{-}$(143 pm) differ because of:

1. Presence of triple bond character in ${\mathrm{BF}}_3$

2. Resonance in $\mathrm{B}{{\mathrm{F}}_4}^{-}$

3. Presence of a double bond character in ${\mathrm{BF}}_3$

4. Presence of a double bond character in $\mathrm{B}{{\mathrm{F}}_4}^{-}$

Despite the dipole moment in the B–Cl bond, the BCl₃ molecule as a whole has no dipole moment because:

CO is a poisonous gas because :

An excessive content of CO₂ is responsible for global warming as:

The sharp decrease in ionization enthalpy from carbon to silicon happens because of-

The correct explanation for the lower atomic radius of Ga as compared to Al is -

1. Poor shielding effect of the 2d-electrons

2. Poor shielding effect of the 3d-electrons

3. Poor shielding effect of the 3p-electrons

4. Poor shielding effect of the 2s-electrons

Amphoteric oxides are:

1. Tl₂O₃, SiO₂

2. ${\mathrm{CO}}_2$, ${\mathrm{B}}_2{\mathrm{O}}_3$

3. ${\mathrm{B}}_2{\mathrm{O}}_3$, ${\mathrm{SiO}}_2$

4. Al₂O₃ , PbO₂