Match List-I with List-II: List - I (a) NaOH (b) \(\mathrm{Be}(\mathrm{OH})_{2}\) (c) \(\mathrm{Ca}(\mathrm{OH})_{2}\) (d) \(\mathrm{B}(\mathrm{OH})_{3}\) (e) \(\mathrm{Al}(\mathrm{OH})_{3}\) List - II (i) Acidic (ii) Basic (iii) Amphoteric Choose the most appropriate answer from the options given below:

(B) (a) - (ii), (b) - (iii), (c) -(ii), (d) -(i), (e) - (iii)

(A) (a) - (ii), (b) - (i), (c) -(ii), (d) -(iii), (e) - (iii)

(C) (a) - (ii), (b) - (ii), (c) -(iii), (d) -(ii), (e)- (iii)

(D) (a) - (ii), (b) - (ii), (c) -(iii), (d) -(i), (e) - (iii)

s-Block Elements — JEE Main · 2021 · 27 Jul 2021 · Shift 1 Question with Solution

Match List-I with List-II:

List - I
(a) NaOH
(b)

Be (OH)_{2}

(c)

Ca (OH)_{2}

(d)

B (OH)_{3}

(e)

Al (OH)_{3}

List - II
(i) Acidic
(ii) Basic
(iii) Amphoteric

Choose the most appropriate answer from the options given below:

Answer: (B)

NaOH and

Ca (OH)_{2}

are hydroxides of strongly electropositive metals, so the

M - O

bond is ionic, hydroxide ions are released in water and both are basic.

B e^{2 +}

and

A l^{3 +}

are small and highly charged, so the

M - O

bond in their hydroxides has appreciable covalent character;

Be (OH)_{2}

and

Al (OH)_{3}

dissolve in acids as the cation and in alkali as the hydroxo anion, and are amphoteric.
In

B (OH)_{3}

boron has only six electrons around it, so it accepts a hydroxide ion from water and sets a proton free,

B (OH)_{3} + 2 H_{2} O ⇌ [B (OH)_{4}]^{-} + H_{3} O^{+}

, which makes it acidic.
So NaOH is basic,

Be (OH)_{2}

amphoteric,

Ca (OH)_{2}

basic,

B (OH)_{3}

acidic and

Al (OH)_{3}

amphoteric.

JEE Main · 2021 · 27 Jul 2021 · Shift 1 · Single correct option