M.C.Q-[Che-1M]

MCQ 11 Mark

Which of the given statement is correct or wrong:
Statement A: Acetic acid freezes at 290 K .
Statement B: Acetic is also called as glacial acetic acid.

A
Statement B is True; Statement A is false.
✓
Statement A is true; Statement B is false.
C
Neither Statement A nor Statement B is
D
Both the statements A and B are true. true.

Answer

Correct option: B.

Statement A is true; Statement B is false.

(B) Both the statements A and B are true.
Explanation: The freezing point of ethanoic acid is $17^{\circ} \mathrm{C}(290 \mathrm{~K})$. When ethanoic acid (acetic acid) is cooled, it freezes to form a colourless, ice-like solid. The solid looks like a glacier and hence pure ethanoic acid are also called glacial ethanoic acid (or glacial acetic acid).

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MCQ 21 Mark

The name of the salt used to remove permanent hardness of water is:

A
Calcium sulphate hemihydrate $\left(\mathrm{CaSO}_{4}\right.$.$\frac{1}{2}H_2 O)$
✓
Sodium carbonate decahydrate ( $\mathrm{Na}_{2} \mathrm{CO}_{3} \cdot 10 \mathrm{H}_{2} \mathrm{O}$ )
C
Sodium hydrogen carbonate $\left(\mathrm{NaHCO}_{3}\right)$
D
Sodium chloride ( NaCl )

Answer

Correct option: B.

Sodium carbonate decahydrate ( $\mathrm{Na}_{2} \mathrm{CO}_{3} \cdot 10 \mathrm{H}_{2} \mathrm{O}$ )

(B) Sodium carbonate decahydrate $\left(\mathrm{Na}_{2} \mathrm{CO}_{3} \cdot 10 \mathrm{H}_{2} \mathrm{O}\right)$
Explanation:Insoluble carbonates are created when washing soda reacts with the salts in water and are easily removed through physical means.

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MCQ 31 Mark

Identify a group of the unsaturated hydrocarbons from the following:

✓
Butyne, Ethene, Propyne
B
Propane, Ethene, Butyne
C
Cyclohexane, Methane, Ethane
D
Ethene, Propane, Hexane

Answer

Correct option: A.

Butyne, Ethene, Propyne

(A) Butyne, Ethene, Propyne

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MCQ 41 Mark

During smelting, an additional substance is added which combines with impurities to form a fusible product known as:

A
Mud
B
Gangue
C
Flux
✓
Slag

Answer

Correct option: D.

Slag

(D) Slag
Explanation:During the smelting of iron, limestone is added as a flux. The temperature inside the blast furnace decomposes limestone to calcium oxide which removes silicate impurity. Impurities like silicon are passed into the slag. The metal is separated from the molten slag.
$\mathrm{CaCO}_{3} \rightarrow \mathrm{CaO}+\mathrm{CO}_{2}$
$\mathrm{CaO}+\mathrm{SiO}_{2} \rightarrow \mathrm{CaSiO}_{3}$ (Slag)

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MCQ 51 Mark

Match the following with the correct response:

Column A	Column B
(i) Catenation	(a) Butene
(ii) Alkane	(b) Carbon compounds
(iii) Alkene	(c) Ethyne
(iv) Alkyne	(d) Ethane

A
(i) - (c), (ii) - (b), (iii) - (d), (iv) - (a)
✓
(i) - (b), (ii) - (d), (iii) - (a), (iv) - (c)
C
(i) - (d), (ii) - (a), (iii) - (c), (iv) - (b)
D
(i) - (a), (ii) - (c), (iii) - (b), (iv) - (d)

Answer

Correct option: B.

(i) - (b), (ii) - (d), (iii) - (a), (iv) - (c)

(B) (i) - (b), (ii) - (d), (iii) - (a), (iv) - (c)
Explanation:
- Carbon forms a large number of compounds due to the property of catenation. Catenation is the linkage of atoms of the same element into longer chains. Catenation occurs most readily in carbon.
- Ethane is an alkane (saturated hydrocarbon with single bonds between the two carbon atoms).
- Butene is an alkene (unsaturated hydrocarbon with double bonds between two carbon atoms).
- Ethyne is an alkyne (unsaturated hydrocarbon with triple bonds between the two carbon atoms).

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MCQ 61 Mark

An element X reacts with $\mathrm{O}_{2}$ to give a compound with a high melting point. This compound is also soluble in water. The element X is likely to be:

A
silicon
B
carbon
C
iron
✓
calcium

Answer

Correct option: D.

calcium

(D) calcium

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MCQ 71 Mark

Select the incorrect statement.
a. The formula of the compound is calcium sulphate dihydrate.
b. When mixed with water and left for half an hour, this compound sets into a hard mass.
c. If heated at higher temperature, the compound becomes dehydrated and is called dead burnt plaster.
d. Both (a) and (b)

A
Statement (d) is incorrect.
B
Statement (a) is incorrect.
✓
Statement (b) is incorrect.
D
Statement (c) is incorrect.

Answer

Correct option: C.

Statement (b) is incorrect.

(C) Statement (b) is incorrect.
Explanation: Atmosphere of Venus is made up of thick white and yellowish clouds of sulphuric acid.

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