Among the various allotropes of carbon:
(A) Diamond is the hardest, lampblack is the softest
(B) Diamond is the hardest, coke is the softest
(C) Coke is the hardest; graphite is the softest
(D) Diamond is the hardest, graphite is the softest

Liquified Petroleum gas contains of mainly--

(A) Methane, ethane and hexane

(B) Ethane, hexane and nonane

(C) Methane, butane and propane

(D) Methane, hexane and nonane

Which of the following is not an isotope of hydrogen ?

(A) Protium

(B) Yttrium

(C) Deuterium

(D) Tritium

Of the metals, which one pollutes the air of a big city?

(A) Copper

(B) Chromium

(C) Lead

(D) Cadmium

Which of the following is not correctly matched ?

Water is a compound because: 
(A) It exists as solid, liquid, or gas.
(B) It contains hydrogen and oxygen.
(C) It has two different elements joined by chemical bonds.
(D) It cannot be split up into simpler substances by chemical means.

Potassium permanganate is used for purifying drinking water because:

(A) It dissolves the impurities of water

(B) It is a sterilizing agent  

(C) It is an oxidizing agent

(D) It reduces agent

When an iron nail gets rusted, iron oxide is formed:

(A) Without any change in the weight of the nail

(B) With increase in the weight of the nail

(C) With decrease in the weight of the nail

(D) Without any change in colour or weight of the nail

Match the following-

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