Question

A laboratory reagent imparts green colour to the flame. On heating with solid $K_{2}C{r}_2{O}_7$ and $conc.H_{2}S{O}_4$ it evolves a red gas. Identify the reagent

• A. $CaC{l}_2$
• B. $BaC{l}_2$
• C. $NaCl$
• D. None of these

Answer 1

The correct option is B $BaC{l}_2$

In flame test, calcium gives yellow red colour, sodium gives yellow colour and barium gives green colour.
$2BaC{l}_2+K_{2}C{r}_2{O}_7+3H_{2}S{O}_4\to K_{2}S{O}_4+2BaS{O}_4+\underset{chromylchloride}{2Cr{O}_{2}C{l}_2}+3H_{2}O$