NEET Chemistry: s-Block Elements questions with solutions

Q1. The correct statement(s) among the following is/are: This question has multiple correct options

1. beryllium oxide is amphoteric in nature.
2. solubility of sulphates of II A group elements decreases down the group.
3. reducing power of hydride of alkali metal decreases down the group.
4. beryllium has diagonal relationship with aluminum.

Answer: beryllium oxide is amphoteric in nature.

Beryllium oxide is amphoteric because Be2+ is very small and highly polarizing, so BeO reacts with both acids and bases. The other statements are not correct as written: Group 2 sulfate solubility decreases down the group, alkali metal hydrides do not show decreasing reducing power down the group in that way, and beryllium’s diagonal relationship is with aluminum.

Q2. \( A l \) has lower ionization potential than that of \( M g \) because:

1. \( A l \) atom is bigger than \( M g \) atom
2. \( M g \) atom is bigger than \( A l \) atom
3. all electrons in \( M g \) are paired, but those of \( A l \) are not
4. all belongs to a higher group

Answer: \( A l \) atom is bigger than \( M g \) atom

Al has a lower ionization potential because its outer electron is easier to remove than Mg’s. In this comparison, the larger atomic size of Al means the valence electron is farther from the nucleus and less strongly attracted.

Q3. \( N a H C O_{3} \) can be used on its own to make cakes or bread. Baking powder is more commonly used, and contains \( N a H C O_{3}, C a\left(H_{2} P O_{4}\right)_{2} \) and starch. An improved combination baking powder contains about \( 40 \% \) starch, \( 30 \% \) \( N a H C O_{3} 20 \% N a A l\left(S O_{4}\right)_{2} \) and \( 10 \% \) \( \boldsymbol{C a}\left(\boldsymbol{H}_{2} \boldsymbol{P} \boldsymbol{O}_{4}\right)_{2} \) Answer the following questions based on above study. n improved baking powder, \( N a A l\left(S O_{4}\right)_{2} \) is used for :

1. makes the decomposition of \( \operatorname{NaH} \mathrm{CO}_{3} \) faster
2. slows the decomposition of \( N a H C O_{3} \)
3. acts as filler
4. makes the bread rise

Answer: slows the decomposition of \( N a H C O_{3} \)

NaAl(SO4)2 is included to reduce the premature breakdown of NaHCO3, helping the powder stay effective during storage. This controlled decomposition prevents loss of CO2 before baking.

Q4. Choose the correct answer form the alternatives given. When alkaline earth metals dissolve in ammonia, they form coloured solution like alkali metals. Which of the following observations regarding the reaction are correct? (i) Dilute solution are bright blue in colour due to solvated electrons. (ii) These solutions decompose to form amides and hydrogen. (iii) From this solution the ammoniates \( \left[M\left(N H_{3}\right)_{6}\right]^{2+} \) can be recovered by evaporation

1. only (i) and (ii)
2. Only (i) and (ii) and (iii)
3. only (ii) and (iii)
4. only (i)

Answer: Only (i) and (ii) and (iii)

All three statements match the known behavior of alkaline earth metals in liquid ammonia: dilute solutions are blue because of solvated electrons, they can decompose to amides and hydrogen, and the hexammine ammoniates can be obtained by evaporation. Therefore, the correct choice includes (i), (ii), and (iii).