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Question

A hydrated metallic salt (A) , light green in colour gives a white anhydrous residue (B) after being heated gradually. (B) is soluble in water and its aqueous solution reacts with NO to give a dark brown compound (C). (B) on strong heating gives a brown residue (D) and a mixture of two gases (E) and (F). The gaseous mixture , when passed through acidified permanganate, discharged the pink colour and when passed through acidified $B a C l_{2}$ solution, gives a white precipitate. Compounds (A), (B), (C) , (D) , (E) and (F) are identified as:
(A) : $F e S O_{4} . 7 H_{2} O$ (B) : $F e S O_{4}$ ,(C) : $F e S O_{4} . N O o r [F e (H_{2} O)_{6} N O] S O_{4}]$ , (D) : $F e_{2} O_{3}$ ,(E) : $S O_{2}$ and (F) : $S O_{3}$
If true enter 1, else enter 0.

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Solution

The light gren hydrated salt (A) is ferrous sulphate, $F e S O_{4} . 7 H_{2} O$ .
When it is gradually heated, a white anhydrous residue (B) is obtained which is $F e S O_{4}$ .
$F e S O_{4}$ is soluble in water and its aqueous solution reacts with NO to give a dark brown compound (C) which is
$F e S O_{4} . N O o r [F e (H_{2} O)_{6} N O] S O_{4}]$ .
$F e S O_{4} + N O \to F e S O_{4} . N O$ or
$F e S O_{4} + 6 H_{2} O + N O \to [F e (H_{2} O)_{6} N O] S O_{4}]$
$F e S O_{4}$ on strong heating gives a brown residue $F e_{2} O_{3}$ and a mixture of two gases $S O_{2}$ and
$S O_{3}$ .
$2 F e S O_{4} h e a t s t r o n g l y - ------- \to F e_{2} O_{3} + S O_{2} ↑ + S O_{3} ↑$
The gaseous mixture, when passed through acidified permanganate, discharged the pink colour and when passed through acidified $B a C l_{2}$ solution, gives a white precipitate of barium sulphate.
$B a C l_{2} + H_{2} O + S O_{3} \to B a S O_{4} + 2 H C l$
$S O_{2}$ gas reduces Mn(VII) to Mn(II) which results in decolourisation.

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Similar questions

Q. Compound (A) is a light green crystalline solid. It gives the following tests:
(i) It dissolves in dilute sulphuric acid. No gas is produced.
(ii) A drop

K M n O_{4}

is added to the above solution. the pink colour disappears.
(iii) Compound (A) is heated strongly. gases (B) and (C) with pungent smell came out. A brown residue (D) is left behind.
(iv) The gas mixture [(B) and (C)] is passed into a dichromate solution. The solution turns green.
(v) The green solution from step (iv) gives a white precipitate (E) with a solution of barium nitrate.
(vi) The residue (D) from (v) is heated on charcoal in reducing the flame. It gives a magnetic substance.

Compound (A) to (E) are identified as:
(A):

F e S O_{4}

S O_{2},

S O_{3}

F e_{2} O_{3}

B a S O_{4}

If true enter 1, else enter 0.

Q. An aqueous solution of salt (A) gives a white crystalline precipitate (B) with NaCl solution. The filtrate gives a black precipitate (C) when

H_{2} S

is passed through it. Compound (B) dissolves in hot water and the solution gives yellow precipitate (D) on treatment with potassium iodine and on cooling. The compound (A) does not give any gas with dilute HCl but liberates a reddish brown gas on heating. Compounds (A) to (D) are identified as:

P b (N O_{3})_{3}

P b C l_{2}

P b S

P b I_{2}

If true enter 1, else enter 0.

Q. Inorganic salt (A) which is hydrated and light green in colour and gives following reactions
(i) (A) decolourizes acidified

M n O_{4}^{-}

and turns acidified

C r_{2} O_{7}^{2 -}

green.
(ii) (A) in aqueous solution gives light green turbidity which dissolves in dil.acid.
(iii) (A) gives white ppt with

B a C l_{2}

solution insoluble in conc. HCl. 2.78 g of (A) gave 2.33 g of white ppt.
(iv) (A)

△ \to (B) (b l a c k i s h b r o w n) + (C) + (D)      o x i d e s o f s u l p h u r

(C) o x i d a t i o n - ------ \to (D)

(C) turns acidified

K_{2} C r_{2} O_{7}

solution green
(B) + HCl

△ \to (E) d e e p y e l l o w

⟶

red colour
Inorganic salt (A) is identified as

F e S O_{4} . 7 H_{2} O

.
If true enter 1, else enter 0.

A black colored compound (A) on reaction with

d i l . H_{2} S O_{4}

gives a gas (B) which on passing in a solution of acid (C) gives white turbidity (D). Gas (B) when passed in an acidified solution of a compound (E) gives a black precipitate (F) which is soluble in hot concentrated (C). After boiling this solution when an excess of ammonia solution is added, a blue-colored compound (G) is formed. To the solution of (E), on the addition of acetic acid and aqueous potassium ferrocyanide, a chocolate brown precipitate (H) is formed. On the addition of an aqueous solution of

B a C l_{2}

to an aqueous solution of (E), white precipitate insoluble in

H N O_{3}

The gas (B) on passing through an acid (C) gives white turbidity (D) because :

Compound (A) is a greenish crystalline salt which gives the following results when tested :

(a) Addition of

B a C l_{2}

solution to a solution of (A) results in the formation of a white precipitate (B) which is insoluble in dilute

H C l

.
(b) On heating, water vapor and two gases (C) and (D) are liberated, leaving a red-brown residue (E).
(c) E dissolves in

c o n c . H C l

to give a yellow solution (F).
(d) With

H_{2} S

, the solution (F) yields a yellow-white ppt. (G) which when filtrated, leaves a greenish filtrate (H).
(e) The solution (F) gives a green solution with

S n C l_{2}

, and when reacted with

K_{4} [F e (C N)_{6}]

gives a blue ppt.

Thus, gases (C) and (D) are :

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