s-Block Elements — JEE Main · 2021 · 27 Jul 2021 · Shift 2 Question with Solution

Match List - I with List - II:

List - I
(a) Li
(b) Na
(c) K
(d) Cs

List - II
(i) photoelectric cell
(ii) absorbent of

CO_{2}

(iii) coolant in fast breeder nuclear reactor
(iv) treatment of cancer
(v) bearings for motor engines

Choose the correct answer from the options given below:

(A)(a) - (v), (b) -(ii), (c) -(iv), (d) -(i)
(B)(a) -(iv), (b) - (iii), (c) -(i), (d) - (ii)
(C)(a) - (v), (b) - (i), (c)- (ii), (d) - (iv)
(D)(a) -(v), (b) - (iii), (c) - (ii), (d) -(i)✓ Correct

Answer: (D)

Solution

Lithium alloyed with lead gives the hard white metal used for bearings in motor engines. Sodium stays liquid over a wide temperature range and conducts heat well, which makes it the coolant in fast breeder nuclear reactors. Potassium burns in excess air to the superoxide

K O_{2}

, which absorbs carbon dioxide while giving out oxygen. Caesium has the lowest ionisation enthalpy of the alkali metals, so ordinary light ejects electrons from it and it is used in photoelectric cells. The matching is Li with bearings for motor engines, Na with coolant in a fast breeder nuclear reactor, K with absorbent of

C O_{2}

, and Cs with photoelectric cell.

JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Single correct option

JEE Main · 2021 · 27 Jul 2021 · Shift 2 · s-Block Elements

Solution

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