13 past paper MCQs on Reactions of Group I Elements, from the s- and p-Block Elements unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.
1.The alkali metals react with chlorine gas to form white metal chloride salts. The metal chloride salt formed is: (MDCAT 2023)
Correct answer: (b) soluble in water to give a neutral solution
Both ions come from a strong base and a strong acid, so neither hydrolyses and the solution is neutral.
2.The difference of lithium from the other alkali metals is mainly because of its: (MDCAT 2024)
Correct answer: (d) small radius and high charge density
The small $\mathrm{Li^+}$ ion concentrates its charge, which is why lithium resembles magnesium more than it resembles sodium.
3.Which of the following alkali metal forms only normal oxide with O2? (KMU MDCAT 2024)
Correct answer: (b) Li
Lithium alone gives the simple oxide; sodium gives a peroxide and the rest give superoxides.
4.Which of the following alkali metal can form normal oxides as well as peroxides? (SZABMU MDCAT 2023)
Correct answer: (a) Na
Sodium gives both the oxide and the peroxide; lithium gives only the oxide.
5.All alkali metals react with chlorine gas to form white metal chlorides salt. The metal chlorides salt formed is: (UHS MDCAT 2023)
Correct answer: (b) Soluble in water to give neutral solution of ph 7
An alkali metal chloride is the salt of a strong acid and a strong base, so its solution is neutral.
6.NaCl can be purified by passing gaseous ________. (PMC MDCAT 2022)
Correct answer: (d) Hydrogen Chloride
Hydrogen chloride raises the chloride concentration and salts the sodium chloride out.
7.Which of the following metal is highly reactive? (PMC MDCAT 2022)
Correct answer: (a) Li
Lithium is an alkali metal and by far the most reactive of these four.
8.Upon burning in air, normal oxide is formed by: (PMC MDCAT 2022)
Correct answer: (a) Li
Lithium alone gives the simple oxide; the heavier alkali metals give peroxides and superoxides.
9.Alkali metal oxides dissolve In water to give: (PMC MDCAT 2022)
Correct answer: (a) Alkaline solution
The oxide takes up water to give the hydroxide, which is a strong alkali.
10.Which of the following property increases down the group in alkali metals? (NUMS MDCAT 2022)
Correct answer: (b) Reactivity
The outer electron is easier to lose down the group, so the metal grows more reactive.
11.Which of the following family is linked with plant ashes? (PMC Practice 2021)
Correct answer: (b) Alkali metals
Alkali means plant ash, and it is the potassium and sodium salts of the ash that gave the group its name.
12.Potassium, Rubidium, Cesium react with oxygen to form which types of oxides? (PMC MDCAT 2020)
Correct answer: (b) Superoxide
The larger alkali metals burn to superoxides; sodium gives a peroxide and lithium the simple oxide.
13.2NaOH(aq) + Cl2(g) → NaCl + NaClO + H2O proceed at: (UHS MDCAT 2016)
Correct answer: (d) 15 °C
Cold dilute alkali gives the chloride and the hypochlorite; hot concentrated alkali would give the chlorate.