CHEMISTRY

1.	The nucleus of an atom consists of
	A. electrons and neutrons B. electrons and protons C. protons and neutrons D. All of the above Answer & Explanation Answer: Option C

2.	The number of moles of solute present in 1 kg of a solvent is called its
	A. molality B. molarity C. normality D. formality Answer & Explanation Answer: Option A

3.	The most electronegative element among the following is
	A. sodium B. bromine C. fluorine D. oxygen Answer & Explanation Answer: Option C

4.	The metal used to recover copper from a solution of copper sulphate is
	A. Na B. Ag C. Hg D. Fe Answer & Explanation Answer: Option D

5.	The number of d-electrons in Fe2+ (Z = 26) is not equal to that of
	A. p-electrons in Ne(Z = 10) B. s-electrons in Mg(Z = 12) C. d-electrons in Fe(Z = 26) D. p-electrons in CI(Z = 17) Answer & Explanation Answer: Option D

6.	The metallurgical process in which a metal is obtained in a fused state is called
	A. smelting B. roasting C. calcinations D. froth floatation Answer & Explanation Answer: Option A

7.	The molecules of which gas have highest speed?
	A. H2 at -73oC B. CH4 at 300 K C. N2 at 1,027oC D. O2 at 0oC Answer & Explanation Answer: Option A

8.	The oldest rocks in the earth's crust were once molten, and came from deep inside the earth. The molten rock, called magma, spewed out in volcanic eruptions during the earth;s early life and solidified into hard rock's called
	A. granite B. basalt C. igneous rocks D. sedimentary rocks Answer & Explanation Answer: Option C

9.	The law which states that the amount of gas dissolved in a liquid is proportional to its partial pressure is
	A. Dalton's law B. Gay Lussac's law C. Henry's law D. Raoult's law Answer & Explanation Answer: Option C

10.	The main buffer system of the human blood is
	A. H2CO3 - HCO3 B. H2CO3 - CO32- C. CH3COOH - CH3COO- D. NH2CONH2 - NH2CONH+ Answer & Explanation Answer: Option A

11.	The gas present in the stratosphere which filters out some of the sun's ultraviolet light and provides an effective shield against radiation damage to living things is
	A. helium B. ozone C. oxygen D. methane Answer & Explanation Answer: Option B

12.	The most commonly used bleaching agent is
	A. alcohol B. carbon dioxide C. chlorine D. sodium chlorine Answer & Explanation Answer: Option C