JEE Main 2021 · 24 Feb · Shift 1 · Chemistry Q57

ChemistryInteger+4 / -1Question 57 of 90

The reaction of sulphur in alkaline medium is given below :

$\mathrm{S_{8(s)}+a\,OH^-_{(aq)}\to b\,S^{2-}_{(aq)}+c\,S_2O_3^{2-}{}_{(aq)}+d\,H_2O_{(l)}}$

The values of 'a' is _______. (Integer answer)

Your answer

Answer and worked solution

Official answer: 12

Balanced $\mathrm{S_8+12OH^-\to4S^{2-}+2S_2O_3^{2-}+6H_2O}$ (sulphur disproportionates to −2 and +2): $a=12$ .

Answer: 12

JEE Main 2021 · 24 Feb · Shift 1, Chemistry question 57