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Standard XIII

Chemistry

Ores and Minerals

A and B are t...

Question

$A$ and $B$ are two ores of copper.
$A$ undergoes calcination to form a solid, $C O_{2 (g)}$ and $O_{2 (g)}$
$B$ 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 $H C l$ 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 copper ores $A$ and $B$ respectively are:

Carbonate and hydroxide

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Carbonate and oxide

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Carbonate and sulphide

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Sulphide and carbonate

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Solution

The correct option is C Carbonate and sulphide
A = $C u (C O_{3})$ and B = $C u S$

Reactions involved are:

Calcination of A:
$C u (C O_{3}) (A) \to C u O (s o l i d) + C O_{2} + O_{2}$

Roasting of B:
$C u S (B) \to C u O (s o l i d) + S O_{2} (C)$

$S O_{2} (C) + K_{2} C r_{2} O_{7} \to K_{2} (S O)_{4} + C r^{3 +} (g r e e n)$

$C u S (B) + d i l . H C l \to C u C l_{2} (s o l i d) + H_{2} S (D)$

$H_{2} S (D) + P b^{2 +} \to P b S (b l a c k)$

$H_{2} S (D) + S O_{2} (C) (m o i s t u r e) \to$ Colloidal sulphur

Suggest Corrections

Similar questions

A

and

B

are two ores of copper.

A

undergoes calcination to form a solid,

C O_{2 (g)}

and

O_{2 (g)}

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

H C l

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:

A

and

B

are two ores of copper.

A

undergoes calcination to form a solid,

C O_{2 (g)}

and

O_{2 (g)}

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

H C l

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 copper ores

A

and

B

respectively are:

Question 33
Write a balanced chemical equation for each of the following reactions and also classify them.

(a) Lead acetate solution is treated with dilute hydrochloric acid to form lead chloride and acetic acid solution.

(b) A piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.

(d) Hydrogen sulphide gas reacts with oxygen gas to form solid sulphur and liquid water.

Q. An amorphous solid

A

burns in air to form a gas

B

which turns lime water milky. This gas is also produced as a by-product during reacting of sulphide ore. This gas decolourises acidified aqueous

K M n O_{4}

solution and reduces

F e^{3 +}

F e^{2 +}

. Identify the solid

A

and the gas

B

and write the reactions involved.

Q. An orange coloured solid

(A)

is soluble in water and gives a gas

(B)

and green coloured solid

(C)

on heating. The compound

(A)

gives a gas

(D)

when reacts with

N a O H

and solution turns yellow. The gas

(D)

turns red litmus blue. Identify the compounds

(A)

(D)

and explain the reaction.

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