All Free Chemistry MCQs with Answers

• A. 3
• B. 4
• C. 5
• D. 6

Explanation: Nitrogen belongs to group number VA. Its electronic configuration is 1s2, 2s2, 2p3. So it has three unpaired electrons in its valence shell.

• A. Oxides of nitrogen are unstable
• B. Catalyst is required for the reaction
• C. The reaction is endothermic
• D. N2 and O2 do not react with each other

Explanation: The reaction between N2 and O2 is endothermic and requires high temperature hence it does not take place naturally in air.

• A. Li
• B. Na
• C. K
• D. Rb

Explanation: Rb has the most number of electronic shell inner to the valence shell, therefore it exhibits the most amount of shielding effect.

• A. Be
• B. Mg
• C. Ca
• D. Ba

Explanation: Barium has the largest atomic size among the options. It is located in the same group (column) as calcium and magnesium but is further…

• A. Be(OH)2
• B. Ca(OH)2
• C. Mg(OH)2
• D. Ba(OH)2

Explanation: Group II metal hydroxides become more soluble in water as you go down the column(group).

• A. Has a higher atomic weight
• B. Is more electronegative
• C. Is more electropositive
• D. Is a metal
• E. Has a high melting point

Explanation: Sodium reacts more vigorously with water than lithium primarily because sodium is more electropositive.

• A. Period 1
• B. Period 2
• C. Period 3
• D. Period 4
• E. Period 5

Explanation: Period 1 of the periodic table consists of only two elements: hydrogen and helium.

• A. Covalent hydrides
• B. Ionic hydrides
• C. Complex hydrides
• D. Metallic hydrides
• E. Polymeric hydrides

Explanation: The correct answer is Ionic hydrides. Ionic hydrides are formed when hydrogen gas is passed over hot alkali or alkaline earth metals…

• A. Sodium carbonate
• B. Sodium bicarbonate
• C. Sodium chloride
• D. Sodium hydroxide
• E. Both B and C

Explanation: The correct answer is Sodium bicarbonate. Sodium bicarbonate, also known as baking soda, is a chemical compound used primarily as a…

• A. Li
• B. K
• C. Ca
• D. Ba
• E. Rb

Explanation: Down the group, the density of the elements increases, and Group II elements have a higher density than Group I elements because of their…

• A. Li
• B. Mg
• C. Sr
• D. Be

Explanation: Group II elements have a higher boiling point than group I elements because of a higher charge, thus better attractive forces, so Li can't…

• A. Peroxide
• B. Superoxide
• C. Suboxide
• D. Normal oxide

Explanation: Li reacts with oxygen to form normal oxide. Na reacts with oxygen to make peroxide.

• A. Mg2N2
• B. Mg3N2
• C. MgN2
• D. MgN

Explanation: Shortcut method: Mg+2 criss-cross charge with N3 to get Mg3N23Mg+ N2 -----> = Mg3 N2

• A. Weak intermolecular forces
• B. Large atomic volume
• C. Smaller size
• D. ns1 configuration

Explanation: The alkali metals have the largest atomic volume due to less no of protons in their nucleus.

• A. P
• B. Na
• C. S
• D. Cl

Explanation: Chlorine does not react with oxygen directly, but the two can react indirectly through other reactions.

• A. 2s
• B. 1s
• C. 2d
• D. 3d

Explanation: OPTION A: Group 2 is alkaline metals. Alkaline earth metals have two electrons in their valence shell and the last electron enters the…

• A. d-block
• B. s-block
• C. f-block
• D. p-block

Explanation: The s-block in the periodic table of elements occupies the alkali metals and alkaline earth metals, also known as groups 1 and 2.

• A. Acidic
• B. Basic
• C. Amphoteric
• D. Neutral

Explanation: Because BeO is insoluble in pure water but reacts with either an acid (like a base would) or a base (like an acid would), we say that it…

• A. I
• B. Cl
• C. Fe
• D. F

Explanation: Halogens are elements present in group 7A of the periodic table and include, Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and…

• A. as antacid
• B. as refractory material
• C. vulcanisation of rubber
• D. all of the above

Explanation: Magnesium oxide is used as antacid because it is a basic oxide and neutralise the acid.