Question

In sodium carbonate bead test, chromium salts (green) change coloured bead to :

• A. yellow, $PbCr{O}_4$
• B. yellow, $BaCr{O}_4$
• C. yellow, ${Na}_{2}Cr{O}_4$
• D. orange, ${Na}_2{Cr}_2{O}_7$

Answer 1

The correct option is C yellow, ${Na}_{2}Cr{O}_4$

$C{r}_2{O}_3\left(green\right)+2N{a}_{2}C{O}_3+\frac{3}{2}{O}_2\to 2N{a}_{2}Cr{O}_4\left(yellow\right)+2C{O}_2$

Sodium chromate formed has yellow color on reaction with $C{r}^{3+}$ in sodium carbonate bead test.