9
MCQ (Single Correct Answer)
Which of the following acids forms three series of salts?
A
$\mathrm{H}_3 \mathrm{PO}_2$
B
$\mathrm{H}_3 \mathrm{BO}_3$
C
$\mathrm{H}_3 \mathrm{PO}_4$
D
$\mathrm{H}_3 \mathrm{PO}_3$
10
MCQ (Single Correct Answer)
Strong reducing behaviour of $\mathrm{H}_3 \mathrm{PO}_2$ is due to
A
low oxidation state of phosphorus
B
presence of two -OH groups and one $\mathrm{P}-\mathrm{H}$ bond
C
presence of one -OH group and two $\mathrm{P}-\mathrm{H}$ bonds
D
high electron gain enthalpy of phosphorus
11
MCQ (Single Correct Answer)
On heating lead nitrate forms oxides of nitrogen and lead. The oxides formed are ............. .
A
$\mathrm{N}_2 \mathrm{O}, \mathrm{PbO}$
B
$\mathrm{NO}_2, \mathrm{PbO}$
C
$\mathrm{NO}, \mathrm{PbO}$
D
$\mathrm{NO}, \mathrm{PbO}_2$
12
MCQ (Single Correct Answer)
Which of the following elements does not show allotropy?
A
Nitrogen
B
Bismuth
C
Antimony
D
Arsenic
13
MCQ (Single Correct Answer)
Maximum covalency of nitrogen is ............ .
A
3
B
5
C
4
D
6