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Standard XII

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 copper ores

A

and

B

respectively are:

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:

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. In a series of reaction during carbon fixation, 'A', a six carbon compound reacts with a three carbon compound to gives rise 'B', a four-carbon compound and 'C', five carbon compound. 'B' reacts with a three carbon compound to form D, a seven carbon compound. 'D' reacts with triose to form two molecules of 'E', five-carbon compounds. Identify the reactant with 'B' and enzyme involved in the formation of 'D' respectively.

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