Q.1 Which of the following alkali metals is the lightest?
Lithium
Sodium
Potassium
Rubidium
Explanation - Lithium has the lowest atomic mass among alkali metals, making it the lightest.
Correct answer is: Lithium
Q.2 Which alkaline earth metal is used in the extraction of titanium from its ore?
Magnesium
Calcium
Strontium
Barium
Explanation - Magnesium is used in the Kroll process to reduce titanium tetrachloride to titanium metal.
Correct answer is: Magnesium
Q.3 Which alkali metal reacts most vigorously with water?
Lithium
Sodium
Potassium
Cesium
Explanation - Reactivity of alkali metals with water increases down the group, so cesium reacts most vigorously.
Correct answer is: Cesium
Q.4 The flame color of calcium salts is:
Red
Orange-red
Yellow
Green
Explanation - Calcium imparts an orange-red color to a flame, used in flame tests to identify it.
Correct answer is: Orange-red
Q.5 Which property decreases down the group in alkali metals?
Electropositivity
Ionization energy
Reactivity with water
Atomic radius
Explanation - Ionization energy decreases down the group due to increasing atomic size and shielding effect.
Correct answer is: Ionization energy
Q.6 Which of the following forms a soluble sulfate?
Barium
Calcium
Strontium
Magnesium
Explanation - Magnesium sulfate is highly soluble in water, whereas barium sulfate is insoluble.
Correct answer is: Magnesium
Q.7 Which alkali metal has the lowest melting point?
Lithium
Sodium
Potassium
Cesium
Explanation - Melting points of alkali metals decrease down the group; cesium has the lowest melting point.
Correct answer is: Cesium
Q.8 Which of the following alkaline earth metals is used in fireworks to produce a crimson color?
Calcium
Strontium
Barium
Magnesium
Explanation - Strontium salts impart a crimson color to fireworks due to excitation of its electrons.
Correct answer is: Strontium
Q.9 Which of the following alkali metals is stored under kerosene due to high reactivity?
Lithium
Sodium
Potassium
All of these
Explanation - All alkali metals are highly reactive with moisture and air, so they are stored under kerosene.
Correct answer is: All of these
Q.10 Which of the following hydroxides is most soluble in water?
LiOH
NaOH
KOH
CsOH
Explanation - Solubility of alkali metal hydroxides increases down the group; cesium hydroxide is the most soluble.
Correct answer is: CsOH
Q.11 Which of the following reacts with nitrogen at high temperature to form a nitride?
Lithium
Sodium
Potassium
Rubidium
Explanation - Lithium reacts with nitrogen to form lithium nitride (Li3N) at elevated temperatures.
Correct answer is: Lithium
Q.12 Which of the following is used as a reducing agent in the extraction of metals like titanium and zirconium?
Magnesium
Calcium
Sodium
Potassium
Explanation - Magnesium is a strong reducing agent and is used in metallothermic reduction of titanium and zirconium.
Correct answer is: Magnesium
Q.13 Which alkali metal is least dense than water?
Lithium
Sodium
Potassium
All of these
Explanation - Lithium, sodium, and potassium all have densities less than water and float on it.
Correct answer is: All of these
Q.14 Which alkaline earth metal imparts a green color to a flame?
Magnesium
Calcium
Strontium
Barium
Explanation - Barium salts give a green flame color, used in pyrotechnics for green fireworks.
Correct answer is: Barium
Q.15 Which property increases down the group in alkaline earth metals?
Ionization energy
Reactivity
Electronegativity
Melting point
Explanation - Reactivity of alkaline earth metals increases down the group due to decreasing ionization energy.
Correct answer is: Reactivity
Q.16 Which alkali metal is used in photoelectric cells?
Lithium
Sodium
Potassium
Cesium
Explanation - Cesium is used in photoelectric cells due to its low ionization energy and ability to emit electrons easily.
Correct answer is: Cesium
Q.17 Which of the following alkali metals reacts with chlorine to form a chloride salt?
Lithium
Sodium
Potassium
All of these
Explanation - All alkali metals react with chlorine to form ionic chloride salts like LiCl, NaCl, and KCl.
Correct answer is: All of these
Q.18 Which alkaline earth metal forms a soluble nitrate used in fireworks?
Magnesium
Calcium
Strontium
Barium
Explanation - Strontium nitrate (Sr(NO3)2) is soluble and is widely used in red fireworks.
Correct answer is: Strontium
Q.19 Which of the following metals is used in alloying to improve the strength of aluminium?
Magnesium
Calcium
Barium
Strontium
Explanation - Magnesium is alloyed with aluminium to improve strength, corrosion resistance, and lightweight properties.
Correct answer is: Magnesium
Q.20 Which alkali metal is used in lithium-ion batteries?
Lithium
Sodium
Potassium
Rubidium
Explanation - Lithium is used in rechargeable lithium-ion batteries due to its small size and high electrochemical potential.
Correct answer is: Lithium
Q.21 Which alkaline earth metal is used in the production of cement?
Calcium
Magnesium
Strontium
Barium
Explanation - Calcium compounds, especially calcium oxide (lime), are used in cement production.
Correct answer is: Calcium
Q.22 Which alkali metal forms superoxides on reaction with oxygen?
Lithium
Sodium
Potassium
Cesium
Explanation - Potassium, rubidium, and cesium form superoxides (KO2, RbO2, CsO2) on reaction with oxygen, but lithium forms normal oxide.
Correct answer is: Potassium
Q.23 Which of the following alkaline earth metals is most abundant in the Earth's crust?
Calcium
Magnesium
Strontium
Barium
Explanation - Calcium is the most abundant alkaline earth metal in the Earth's crust, mainly as limestone and gypsum.
Correct answer is: Calcium
Q.24 Which alkali metal is used as a heat transfer medium in nuclear reactors?
Lithium
Sodium
Potassium
Rubidium
Explanation - Liquid sodium is used as a heat transfer medium in fast breeder reactors due to its high thermal conductivity.
Correct answer is: Sodium
Q.25 Which of the following compounds is used to remove hardness of water?
Calcium carbonate
Sodium carbonate
Magnesium hydroxide
Barium sulfate
Explanation - Sodium carbonate (washing soda) reacts with Ca2+ and Mg2+ ions to remove water hardness.
Correct answer is: Sodium carbonate