Consider the following reactions: \(\mathrm{NaCl}+\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}+\mathrm{H}_{2} \mathrm{SO}_{4} \rightarrow \mathrm{~A}+\mathrm{KHSO}_{4}+\mathrm{NaHSO}_{4}+\mathrm{H}_{2} \mathrm{O}\) \(\mathrm{A}+\mathrm{NaOH} \rightarrow \mathrm{B}+\mathrm{NaCl}+\mathrm{H}_{2} \mathrm{O}\) \(\mathrm{B}+\mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{H}_{2} \mathrm{O}_{2} \rightarrow \mathrm{C}+\mathrm{Na}_{2} \mathrm{SO}_{4}+\mathrm{H}_{2} \mathrm{O}\) In the product ' C ', ' X ' is the number of \(\mathrm{O}_{2}^{2-}\) units, ' Y ' is the total number oxygen atoms present and ' \(Z\) ' is the oxidation state of Cr . The value of \(\mathrm{X}+\mathrm{Y}+\mathrm{Z}\) is \_\_\_\_。

JEE Main · 2026 · 21 Jan 2026 · Shift 1 · d and f Block Elements

Consider the following reactions:

NaCl + K_{2} Cr_{2} O_{7} + H_{2} SO_{4} \to A + KHSO_{4} + NaHSO_{4} + H_{2} O

A + NaOH \to B + NaCl + H_{2} O

B + H_{2} SO_{4} + H_{2} O_{2} \to C + Na_{2} SO_{4} + H_{2} O

In the product ' C ', ' X ' is the number of

O_{2}^{2 -}

units, ' Y ' is the total number oxygen atoms present and '

Z

' is the oxidation state of Cr . The value of

X + Y + Z

is ____。

Answer: 13

Sodium chloride with potassium dichromate and concentrated sulphuric acid gives red chromyl chloride vapour, so A is CrO

_{2}

_{2}

. Chromyl chloride with sodium hydroxide gives sodium chromate, so B is Na

_{2}

CrO

_{4}

. Acidified chromate with hydrogen peroxide gives blue chromium peroxide, so C is CrO

_{5}

. In CrO

_{5}

the chromium holds one doubly bonded oxygen and two peroxide (

O_{2}^{2 -}

) units, so the number of peroxide units is

X = 2

and the total number of oxygen atoms is

Y = 5

; balancing the charges,

Cr + (- 2) + 2 (2 \times - 1) = 0

gives the chromium oxidation state

Z = + 6

. Therefore

X + Y + Z = 2 + 5 + 6 = 13

JEE Main · 2026 · 21 Jan 2026 · Shift 1 · Integer answer