Question

Two zinc rods are placed in contact with dil. $HN{O}_3$ and conc. $HN{O}_3$ in two separate containers A and B. The characteristics of gases evolved in the containers are respectively:

• A. The gas in container A turns $K_{2}C{r}_2{O}_7$ green and the gas in container B turns lead acetate black.
• B. A $\to$ Pungent smelling gas, B $\to$ colourless, odourless gas.
• C. A $\to$ Inflammable gas, B $\to$ Turns $K_{2}C{r}_2{O}_7$ green.
• D. A $\to$ Can react with $O_2$ explosively, B $\to$ No reaction with $O_2$ at all.

Answer 1

Answer: (C)

A $\to$ Inflammable gas, B $\to$ Turns $K_{2}C{r}_2{O}_7$ green.

$4Zn+10HN{O}_3\left(dil\right)\to 4Zn(N{O}_3{)}_2+5H_{2}O+N_{2}O$
$Zn+4HN{O}_3(conc.)\to Zn(N{O}_3{)}_2+2H_{2}O+2N{O}_2$
$N{O}_2$ turns orange $K_{2}C{r}_2{O}_7$ green.
$N_{2}O$ is inflammable.