Question

Given an element having following ionisation enthalpies IE₁ = 496 kJ/mol and IE₂ = 4562 kJ/mol one mole hydroxide of this element is treated separated with HCl and H₂SO₄ respectively. Moles of HCl and H2SO4 reacted respectively is

(1) 1, 0.5 

(2) 0.5, 1 

(3) 2, 0.5 

(4) 0.5, 2 

Answer 1

The answer is (1) 1, 0.5

According to the given data of I.E, This element must belong to group 1 and thus is monovalent & form hydroxide of the type M(OH).

MOH + HCl→MCl + H₂O

1 mole 1 mole

2MOH + H₂SO₄→ M₂SO₄ + H₂O

1 mole 1/2 mole.