Crude petroleum is converted to useful products by the process of?

• A. fractional crystallization
• B. fractional distillation
• C. filtration
• D. chromatography

In the redox reaction represented by the following equation: Cu²⁺+aq Zn(s) → Cu(s) + Zn²⁺

• A. the oxidation number of copper increases
• B. copper (ll) ions are reduced to copper atoms
• C. zinc atoms are reduced to zinc ions
• D. copper (ll) ions donate electrons to zinc atoms

The purest from of iron which contains only about 0.1% carbon is

• A) pig iron
• B) wrough iron
• C) cast iron
• D) iron pyrite

When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to

• A. condense
• B. evaporate
• C. sublime
• D. precipitate

In the shown experiment (Fig. 1) the litmus paper will initially

• A) be bleached
• B) turn green
• C) turn red
• D) turn blue

Which of the following metals is not extracted by electrolysis ?

• A. lron
• B. Sodium
• C. Calcium
• D. Magnesium

Cu2S(s) + O2(g) = 2CU(s) + SO22(g)

• A) +1 to 0
• B) 0 to +2
• C) +2 to +1
• D) 0 to +1

Consider the reaction represented by the following equation: xKMnO₄(aq) + ySO₂(g) + zH₂O(I) → K₂SO₄(AQ) + 2MnSO₄(aq) + 2H₂SO x,y and z are respectively

• A. 2,5 and 2
• B. 2,2 and 5
• C. 5, 1 and 2
• D. 1, 5 and 2

Water for town supply is chlorinated to make it free from?

• A. bad odour
• B. bacteria
• C. temporary hardness
• D. permanent hardness

Which of the following compounds crystallizes without water of crystallization?

• A. MgSO4
• B. Na2CO3
• C. NaCI
• D. FeSO4