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

MCQ 11 Mark

Which of the following substances produce hydrogen on reacting with metals?

A
Water ( $\mathrm{H}_{2} \mathrm{O}$ )
B
$\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$
C
$\mathrm{H}_{2} \mathrm{SO}_{4}$
D
All of these

Answer

(D) All of these
Explanation:
All of these produce hydrogen on reacting with metals.
- Metal + Water $\rightarrow$ Metal hydroxide + Hydrogen
- Metal + Steam $\rightarrow$ Metal oxide + Hydrogen (only those metals displace hydrogen from water (or steam) which are above hydrogen in the reactivity series.
- Metal + Acid $\rightarrow$ Metal salt + Hydrogen
- $2 \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}+\mathrm{Na} \rightarrow 2 \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{ONa}+\mathrm{H}_{2}$ (This reaction is used as a test for ethanol).

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MCQ 21 Mark

Which of the following gives the correct increasing order of acidic strength?
a. Sodium chloride < Acetic acid < Hydrochloric acid
b. Sodium chloride < Hydrochloric acid < Acetic acid
c. Acetic acid < Sodium chloride < Hydrochloric acid
d. Hydrochloric acid < Sodium chloride < Acetic acid

A
Sodium chloride < Acetic acid < Hydrochloric acid
B
Acetic acid < Sodium chloride < Hydrochloric acid
C
Hydrochloric acid < Sodium chloride < Acetic acid
D
Sodium chloride < Hydrochloric acid < Acetic acid

Answer

(A) Sodium chloride $<$ Acetic acid $<$ Hydrochloric acid
Explanation:
Since NaCl is neutral, acetic acid is weak, and HCl is strong, the correct order is: Sodium chloride < Acetic acid < Hydrochloric acid

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MCQ 31 Mark

Consider the structures of the three cyclic carbon compounds A, B and C given below and select the correct option from the following:

A
A and C are isomers of hexane and B is benzene.
B
A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic hydrocarbons.
C
A is an isomer of hexane, B is benzene and C is an isomer of hexene.
D
A is cyclohexane and B and C are the isomers of benzene.

Answer

(A) A and C are isomers of hexane and B is benzene.
Explanation:
A and C are isomers of hexane and B is benzene.

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MCQ 41 Mark

The following diagram shows the electrolytic refining of copper:

Which of the following statements is incorrect description of the process?

A
The impure metal from the anode dissolves into the electrolyte.
B
Insoluble impurities settle down at the bottom of the anode.
C
On passing the current through the electrolyte, the pure metal from the anode dissolves into the electrolyte.
D
The pure metal from the electrolyte is deposited on the cathode.

Answer

(C) On passing the current through the electrolyte, the pure metal from the anode dissolves into the electrolyte.
Explanation:
When current is passed through the electrolyte, the impure metal from the anode is dissolved in the electrolyte and an equal amount of pure metal from the electrolyte is deposited on the cathode.

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MCQ 51 Mark

Match the following with the correct response:

Column A	Column B
(i) Welding	(a) Ethyl alcohol
(ii) Fuel in a spirit lamp	(b) Ester
(iii) Lime water turns milky	(c) Carbon dioxide
(iv) Fruity smell	(d) Ethyne and oxygen

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

Answer

(D) (i) - (d), (ii) - (a), (iii) - (c), (iv) - (b)
Explanation:
- The oxyacetylene welding process uses a combination of ethyne $\left(\mathrm{C}_{2} \mathrm{H}_{2}\right)$ and oxygen gas to provide a high-temperature flame. It is commonly used to permanently join mild steel.
- Alcohol meant for industrial purposes (fuel for spirit lamps) is made unfit for human consumption by adding small amounts (about 5%) of methanol to alcohol. The mixture is known as denatured spirit or denatured alcohol.
- Carbon dioxide turns lime water turns milky due to the formation of insoluble calcium carbonate.
- Esters have a fruity smell and are used in perfumes and cosmetics due to their characteristic odour.

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MCQ 61 Mark

A metal $\mathbf{X}$ is used in thermit process. When $\mathbf{X}$ is heated with oxygen, it gives an oxide $\mathbf{Y}$, which is amphoteric in nature. $\mathbf{X}$ and $\mathbf{Y}$ respectively are:

A
$\mathrm{Fe}, \mathrm{Fe}_{2} \mathrm{O}_{3}$
B
$\mathrm{Mg}, \mathrm{MgO}$
C
$\mathrm{Mn}, \mathrm{MnO}_{2}$
D
$\mathrm{Al}, \mathrm{Al}_{2} \mathrm{O}_{3}$

Answer

(D) $\mathrm{Al}, \mathrm{Al}_{2} \mathrm{O}_{3}$
Explanation:
$Al , Al _2 O _3$

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MCQ 71 Mark

Which of the given statement is true or false:
Statement A: Valeric acid is the common name of hexane.
Statement B: Glycerol is added in the manufacturing of soap.

A
Statement $B$ is true and statement $A$ is false
B
Neither statement $A$ nor statement $B$ is false
C
Both the statements A and B are false
D
Statement A is true and statement B is false

Answer

(C) Both the statements A and B are false
Explanation:
Valeric acid is another name for pentanoic acid. Soaps are sodium or potassium salts of long-chain fatty acids. When triglycerides in fat/oil react with aqueous NaOH or KOH , they are converted into soap and glycerol.

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MCQ 81 Mark

Find the incorrect statement:
A. The pH of the stomach is approximately 4.5
B. Plants grow well in natural soil
C. The pH of acid rain is nearly 5.6
D. The pH of rainwater is nearly 7

A
Statement (B)
B
Statement (D)
C
Statement (C)
D
Statement (A)

Answer

(D) Statement (A)
Explanation:
The human stomach produces gastric juices which contain hydrochloric acid in them resulting in a pH of 1.4.

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