The strongest hydrogen bond present among the following is-

1. $\mathrm{O}—\mathrm{H}‐‐‐\mathrm{S}$

2. $\mathrm{S}—\mathrm{H}‐‐‐\mathrm{O}$

3. $\mathrm{F}—\mathrm{H}‐‐‐\mathrm{F}$

4. $\mathrm{F}—\mathrm{H}‐‐‐\mathrm{O}$

In which of the process, the bond order increases and magnetic behaviour changes?

(a) $N_2\to {N_2}^{+}$

(b) $C_2\to {C_2}^{+}$

(c) $NO\to N{O}^{+}$

(d) $O_2\to {O_2}^{+}$

In piperidine "N" atom has hybridization:

1. sp

2. $s{p}^2$

3. $s{p}^3$

4. $ds{p}^2$

The coordination geometry around and hybridization of N and B atoms in a 1:1 complex of NH₃ and BF₃ ${\mathrm{is}}_{}$:

(1) N: tetrahedral, sp³;  B: tetrahedral, sp³

(2) N: pyramidal, sp³; B: pyramidal, sp³

(3) N: pyramidal, sp³; B: planar, sp²

(4) N: pyramidal, sp³; B: tetrahedral, sp³

Assuming $2s-2p$ mixing is NOT operative, the paramagnetic species among the following is :

(1) $B{e}_2$

(2) $B_2$

(3) $C_2$

(4) $N_2$

When $O_2$ is adsorbed on a metallic surface, electron transfer occurs from the ,metal to $O_2$. The wrong statements(s) regarding this adsorption is (are): 

(1) $O_2$ is physisorbed 

(2) Heat is released

(3) Occupancy of $\pi *2p$ of $O_2$ is increased 

(4) Bond length of $O_2$ is increased

Born Haber cycle is used to determine:

(1) lattice energy 

(2) electron affinity 

(3) ionization energy 

(4) either of them 

The molecule having the smallest bond angle is-

Select the most ionic and most covalent compounds respectively from the following.

$Cr{O}_5,M{n}_2{O}_7,PbO, P_4{O}_{10}, Sn{O}_2$

(A) $Cr{O}_5, M{n}_2{O}_7$                                (B)  $PbO, M{n}_2{O}_7$

(C) $Cr{O}_5, P_4{O}_{10}$                                 (D) $Sn{O}_2, Cr{O}_5$

In which of the following sets the central atom of each member involves $s{p}^3$ hybridisation?

(A) $I{O_4}^{‐}IC{l_4}^{‐}and I{F_4}^{+}$                                      (B) $Xe{O}_3, Xe{O}_4, Xe{F}_4$

(C) $S{O}_3,\hspace{0.17em}S{O_3}^{2‐}, S{O_4}^{2‐}$                                    (D) $PC{l_4}^{+}, B{F_4}^{‐}, Cl{O_4}^{‐}$