Q23 / 125 · BITSAT 2019 · Chemistry

Which of the following compounds, on reaction with $NaOH$ and ${Na}_{2} O_{2}$ gives yellow colour?

A
$Zn {(OH)}_{2}$
B
$Al {(OH)}_{3}$
Correct answer
C
$Cr {(OH)}_{3}$
D
${CaCO}_{3}$

Solution

Chromium hydroxide, i.e. $Cr {(OH)}_{3}$ when reacts with $NaOH$ and ${Na}_{2} O_{2}$ , gives yellow colour of sodium chromate. The whole reaction is as follows

$3 {Na}_{2} O_{2} + 2 Cr {(OH)}_{3} ⟶ \underset{(yellow)}{2 {Na}_{2} {CrO}_{4}} + 2 H_{2} O + 2 NaOH$

Hence, the correct answer is option: 'C'.

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Solution

More Practical Chemistry Questions

Which of the following compounds, on reaction with $NaOH$ and ${Na}_{2} O_{2}$ gives yellow colour?