Question

A white colored salt forms white sublimate in dry heating test and also gives ammonia on heating with, caustic soda solution. Which of the following test will be shown positive by the salt?

• A. It will give greenish yellow gas on reaction with $conc.H_{2}S{O}_4$
• B. It will give red gas by heating with $K_C{r}_2{O}_7$ and $conc.H_{2}S{O}_4$
• C. It will give colorless gas with $dil.H_{2}S{O}_4$
• D. It will give ring test

Answer 1

The correct option is B It will give red gas by heating with $K_C{r}_2{O}_7$ and $conc.H_{2}S{O}_4$

A white colored salt (ammonium chloride $N{H}_{4}Cl$ ) forms white sublimate in dry heating test and also gives ammonia on heating with, caustic soda solution.
$N{H}_{4}Cl+NaOH\to NaCl+N{H}_3\uparrow +H_{2}O$

It will give red gas (of chromyl chloride $Cr{O}_{2}C{l}_2$) by heating with $K_{2}C{r}_2{O}_7$ and conc.$H_{2}S{O}_4$
$4N{H}_{4}Cl+K_{2}C{r}_2{O}_7+3H_{2}S{O}_4\to K_{2}S{O}_4+2(N{H}_4{)}_{2}S{O}_4+2Cr{O}_{2}C{l}_2\uparrow +3H_{2}O$