Q.1 Which of the following elements has the highest reactivity among alkali metals?
Lithium
Sodium
Potassium
Rubidium
Explanation - Reactivity of alkali metals increases down the group due to the decreasing ionization energy.
Correct answer is: Rubidium
Q.2 What is the common oxidation state of alkaline earth metals?
+1
+2
+3
+4
Explanation - Alkaline earth metals have two valence electrons, which they commonly lose to form +2 cations.
Correct answer is: +2
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; cesium reacts explosively.
Correct answer is: Cesium
Q.4 Which of the following compounds is insoluble in water?
NaCl
KBr
Mg(OH)2
Ca(NO3)2
Explanation - Most hydroxides of alkaline earth metals are sparingly soluble, Mg(OH)2 being one of them.
Correct answer is: Mg(OH)2
Q.5 Which of the following properties increases down the group in alkali metals?
Electronegativity
Ionization energy
Atomic radius
Melting point
Explanation - Atomic radius increases down the group due to addition of electron shells.
Correct answer is: Atomic radius
Q.6 Which alkaline earth metal is used in the extraction of titanium from its ore?
Beryllium
Magnesium
Calcium
Strontium
Explanation - Magnesium reduces TiCl4 to titanium metal in the Kroll process.
Correct answer is: Magnesium
Q.7 Which alkali metal is least dense?
Lithium
Sodium
Potassium
Rubidium
Explanation - Lithium is the lightest alkali metal with the lowest density.
Correct answer is: Lithium
Q.8 Which of the following is used in the manufacture of soap?
NaOH
KOH
CaO
MgO
Explanation - Sodium hydroxide (NaOH) is used in saponification to make soap.
Correct answer is: NaOH
Q.9 Which alkaline earth metal is used as a desiccant due to its strong affinity for water?
Beryllium
Magnesium
Calcium
Calcium oxide
Explanation - CaO (quicklime) absorbs water to form Ca(OH)2, acting as a desiccant.
Correct answer is: Calcium oxide
Q.10 Which alkali metal has the lowest melting point?
Lithium
Sodium
Potassium
Cesium
Explanation - Melting points decrease down the group as metallic bonding weakens with larger atomic size.
Correct answer is: Cesium
Q.11 Which alkaline earth metal is toxic and used in aerospace alloys?
Beryllium
Magnesium
Calcium
Strontium
Explanation - Beryllium is lightweight, strong, and toxic; used in aerospace and nuclear applications.
Correct answer is: Beryllium
Q.12 Which of the following is formed when sodium reacts with chlorine?
NaCl2
Na2Cl
NaCl
NaClO
Explanation - Sodium reacts with chlorine to form sodium chloride (NaCl) in a 1:1 ratio.
Correct answer is: NaCl
Q.13 Which of the following is not an alkali metal?
Sodium
Potassium
Calcium
Lithium
Explanation - Calcium belongs to group 2 (alkaline earth metals), not group 1.
Correct answer is: Calcium
Q.14 Which property of alkali metals decreases down the group?
Atomic radius
Electronegativity
Reactivity with water
Density
Explanation - Electronegativity decreases down the group because atoms hold valence electrons less tightly.
Correct answer is: Electronegativity
Q.15 Which alkali metal reacts with oxygen to form peroxide?
Lithium
Sodium
Potassium
Rubidium
Explanation - Sodium forms sodium peroxide (Na2O2) on reaction with oxygen.
Correct answer is: Sodium
Q.16 Which alkaline earth metal imparts a brick-red color to flame?
Beryllium
Calcium
Magnesium
Strontium
Explanation - Strontium compounds emit red color in flame tests.
Correct answer is: Strontium
Q.17 Which alkali metal is stored under kerosene due to its high reactivity?
Lithium
Sodium
Potassium
Rubidium
Explanation - Potassium reacts violently with moisture and air, hence stored under kerosene.
Correct answer is: Potassium
Q.18 Which of the following is a major constituent of bones and teeth?
Magnesium
Calcium
Beryllium
Strontium
Explanation - Calcium phosphate and carbonate are key components of bones and teeth.
Correct answer is: Calcium
Q.19 Which alkali metal is used in photoelectric cells?
Lithium
Sodium
Potassium
Cesium
Explanation - Cesium has low ionization energy and is used in photoelectric cells.
Correct answer is: Cesium
Q.20 Which alkali metal is essential in human diet for nerve function?
Lithium
Sodium
Potassium
Rubidium
Explanation - Potassium ions are crucial for nerve impulse transmission and muscle contraction.
Correct answer is: Potassium
Q.21 Which of the following oxides is amphoteric?
Li2O
BeO
Na2O
K2O
Explanation - Beryllium oxide reacts with both acids and bases, showing amphoteric behavior.
Correct answer is: BeO
Q.22 Which alkaline earth metal hydroxide is most soluble in water?
Mg(OH)2
Ca(OH)2
Sr(OH)2
Ba(OH)2
Explanation - Solubility of hydroxides increases down the group; Ba(OH)2 is highly soluble.
Correct answer is: Ba(OH)2
Q.23 Which element forms a hydride that is a reducing agent used in organic chemistry?
Lithium
Sodium
Potassium
Calcium
Explanation - Lithium hydride (LiH) is a strong reducing agent used in chemical reactions.
Correct answer is: Lithium
Q.24 Which alkali metal forms a hydroxide that is least soluble in water?
Lithium
Sodium
Potassium
Rubidium
Explanation - Lithium hydroxide is less soluble than other alkali metal hydroxides.
Correct answer is: Lithium
Q.25 Which alkaline earth metal is used in flares to produce a bright white light?
Calcium
Strontium
Barium
Magnesium
Explanation - Magnesium burns with a bright white flame and is used in flares and fireworks.
Correct answer is: Magnesium