19
MCQ (Single Correct Answer)
The oxidation state of central atom in the anion of compound $\mathrm{NaH}_2 \mathrm{PO}_2$ will be ........... .
A
+3
B
+5
C
+1
D
$-$3
20
MCQ (Single Correct Answer)
Which of the following is not tetrahedral in shape?
A
$\mathrm{NH}_4^{+}$
B
$\mathrm{SiCl}_4$
C
$\mathrm{SF}_4$
D
$\mathrm{SO}_4{ }^{2-}$
21
MCQ (Single Correct Answer)
Which of the following are peroxoacids of sulphur?
A
$\mathrm{H}_2 \mathrm{SO}_5$ and $\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_8$
B
$\mathrm{H}_2 \mathrm{SO}_5$ and $\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_7$
C
$\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_7$ and $\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_8$
D
$\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_6$ and $\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_7$
22
MCQ (Single Correct Answer)
Hot conc. $\mathrm{H}_2 \mathrm{SO}_4$ acts as moderately strong oxidising agent. It oxidises both metals and non-metals. Which of the following element is oxidised by conc. $\mathrm{H}_2 \mathrm{SO}_4$ into two gaseous products?
A
Cu
B
S
C
C
D
Zn
23
MCQ (Single Correct Answer)
A black compound of manganese reacts with a halogen acid to give greenish yellow gas. When excess of this gas reacts with $\mathrm{NH}_3$ an unstable trihalide is formed. In this process the oxidation state of nitrogen changes from ............ .
A
$-$3 to +3
B
$-$3 to 0
C
$-$3 to +5
D
0 to $-$3