3
MCQ (Single Correct Answer)
In a cyclotrimetaphosphoric acid molecule, how many single and double bonds are present?
A
3 double bonds; 9 single bonds
B
6 double bonds; 6 single bonds
C
3 double bonds; 12 single bonds
D
Zero double bond; 12 single bonds
4
MCQ (Single Correct Answer)
Which of the following elements can be involved in $p \pi-d \pi$ bonding?
A
Carbon
B
Nitrogen
C
Phosphorus
D
Boron
5
MCQ (Single Correct Answer)
Which of the following pairs of ions are isoelectronic and isostructural?
A
$\mathrm{CO}_3^{2-}, \mathrm{NO}_3^{-}$
B
$\mathrm{CIO}_3^{-}, \mathrm{CO}_3^{2-}$
C
$\mathrm{SO}_3^{2-}, \mathrm{NO}_3^{-}$
D
$\mathrm{ClO}_3^{-}, \mathrm{SO}_3^{2-}$
6
MCQ (Single Correct Answer)
Affinity for hydrogen decreases in the group from fluorine to iodine. Which of the halogen acids should have highest bond dissociation enthalpy?
A
HF
B
HCl
C
HBr
D
HI
7
MCQ (Single Correct Answer)
Bond dissociation enthalpy of $\mathrm{E}-\mathrm{H}$ ( $\mathrm{E}=$ element) bonds is given below. Which of the compounds will act as strongest reducing agent?
| Compound | $\mathrm{NH_3}$ | $\mathrm{PH_3}$ | $\mathrm{AsH_3}$ | $\mathrm{SbH_3}$ |
|---|---|---|---|---|
| $\Delta_{\text {diss }}(E-H) / \mathrm{kJ} \mathrm{mol}^{-1}$ |
389 | 322 | 297 | 255 |
A
$\mathrm{NH_3}$
B
$\mathrm{PH_3}$
C
$\mathrm{AsH_3}$
D
$\mathrm{SbH_3}$