A sulphate of a metal (M) on healing evolves two gases (B) and (C) and an oxide (D). Gas (B) turns acidified dichromate paper green while gas (C) forms a trimer. Compound (D) forms a Lewis acid (E) with HCl (g).
If, the number of S -S bonds in trimer of gas (C) be 'n' and the number of equivalent M-Cl bonds in one molecule of anhydrous (E) be 'm', Then, (m + n) is:

Q. A sulphate of a metal (A) on heating evolves two gases (B) and (C) and an oxide (D). Gas (B) turns $K_{2}C{r}_2{O}_7$ paper green while gas (C) forms a trimer in which there is no S-S bond. Compound (D) with conc. HCl forms a Lewis acid (E) which exists in a dimer. Compounds (A), (B), (C), (D) and (E) are respectively:

Q. An organic compound (A) on heating produces two gases (B) and (C) and neutral oxide (D) which turns cobalt chloride paper pink. Gas (B) turns lime water milky and produces an acidic solution, with water. Gas (C) produces a poisonous gas (E) with chlorine gas, this gas with ammonia gives an organic compound (F) which on further reaction with (D) gives $N{H}_3$ gas. Then, compounds (A) and (F) can be found as:

Q. $A$ and $B$ are two ores of copper.
$A$ undergoes calcination to form a solid, $C{O}_{2\left(g\right)}$ and $O_{2\left(g\right)}$
$B$ undergoes roasting to form a solid and a gas $C$ which turns acidified $K_{2}C{r}_2{O}_7$ to green solution.
$B$ also reacts with dil $HCl$ to form a solid and gas $D$ which turns lead acetate solution black. $D$ also reacts with $C$ to form colloidal sulphur in the presence of moisture.

The gas ($C$) acts as a/an:

Q. Salts A, B, C, D and E undergo reactions (i) to (v) respectively. Identify the anion present in these salts on the basis of these reactions. Tabulate your answers in the format given below:
(i) When silver nitrate solution is added to a solution of A, a white precipitate, insoluble in dilute nitric acid, is formed.
(ii) Addition of dilute hydrochloric acid to B produces a gas which turns lead acetate paper black.
(iii) When a freshly prepared solution of ferrous sulphate is added to a solution of C and concentrated sulphuric acid is gently poured from the side of the test tube, a brown ring is formed.
(iv) When dilute sulphuric acid is added to D, a gas is produced which turns acidified potassium dichromate solution from orange to green.
(v) Addition of dilute hydrochloric acid to E produces an effervescence. The gas produced turns limewater milky but does not affect acidified potassium dichromate solution.

Salt	Anion
A
B
C
D
E

Q. $A$ and $B$ are two ores of copper.
$A$ undergoes calcination to form a solid, $C{O}_{2\left(g\right)}$ and $O_{2\left(g\right)}$
$B$ undergoes roasting to form a solid and a gas $C$ which turns acidified $K_{2}C{r}_2{O}_7$ to green solution.
$B$ also reacts with dil $HCl$ to form a solid and gas $D$ which turns lead acetate solution black. $D$ also reacts with $C$ to form colloidal sulphur in the presence of moisture.

The nature of the gas ($D$) and hybridization of the central atom is respectively: