JEE Main 2018 — Chemistry Inorganic Chemistry

2018mcqeasy

The oxidation states of $\mathrm{Cr}$ in $[\mathrm{Cr}{({H}_{2}O)}_{6}]{\mathrm{Cl}}_{3}, [\mathrm{Cr}{({C}_{6}{H}_{6})}_{2}]$ and ${K}_{2}[\mathrm{Cr}{(\mathrm{CN})}_{2}{(O)}_{2}({O}_{2})({\mathrm{NH}}_{3})]$ , respectively, are:

Official previous-year question

Held on 8 Apr 2018 · Verified 6 Jul 2026.

Options

A
$+3, 0$ and $+4$
B
$+3, +4$ and $+6$
C
$+3, +2$ and $+4$
D
$+3, 0$ and $+6$

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Solution

(i) $[\mathrm{Cr}{({H}_{2}O)}_{6}]{\mathrm{Cl}}_{3}:$ Hexaaquachromium $(\mathrm{III})$ chloride

$x+6\times 0+(-1)\times 3=0$

$x=+3$

(ii) $[\mathrm{Cr}{({C}_{6}{H}_{6})}_{2}]:\mathrm{bis} ({\eta }^{6}-\mathrm{benzene})$ chromium $(0)$

$y+2\times 0=0$

$y=0$

(iii) ${K}_{2}[\mathrm{Cr}{(\mathrm{CN})}_{2}{(O)}_{2}({O}_{2})({\mathrm{NH}}_{3})]:$ Potassium amminedicyanido dioxide peroxide chromate $(\mathrm{VI})$

$2\times 1+z+2\times (-1)+2\times (-2)+(-2)+0=0$

$z=+6$

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Solution

(i) $[\mathrm{Cr}{({H}_{2}O)}_{6}]{\mathrm{Cl}}_{3}:$ Hexaaquachromium $(\mathrm{III})$ chloride

$x+6\times 0+(-1)\times 3=0$

$x=+3$

(ii) $[\mathrm{Cr}{({C}_{6}{H}_{6})}_{2}]:\mathrm{bis} ({\eta }^{6}-\mathrm{benzene})$ chromium $(0)$

$y+2\times 0=0$

$y=0$

(iii) ${K}_{2}[\mathrm{Cr}{(\mathrm{CN})}_{2}{(O)}_{2}({O}_{2})({\mathrm{NH}}_{3})]:$ Potassium amminedicyanido dioxide peroxide chromate $(\mathrm{VI})$

$2\times 1+z+2\times (-1)+2\times (-2)+(-2)+0=0$

$z=+6$

JEE Main 2018 — Chemistry Inorganic Chemistry

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JEE Main 2018 — Chemistry Inorganic Chemistry

Options

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Solution

Your note

JEE Main Inorganic Chemistry in other years

More JEE Main Inorganic Chemistry questions

Other Chemistry topics for JEE Main

Physical Chemistry

Organic Chemistry

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