The energy required to convert all the atoms of magnesium to magnesium ions present in 24 mg of magnesium vapours is (First and second ionization enthalpies of Mg are 737.76 and 1450.73 KJ mol-1 respectively).

Question

The energy required to convert all the atoms of magnesium to magnesium ions present in 24 mg of magnesium vapours is (First and second ionization enthalpies of Mg are 737.76 and 1450.73 KJ mol-1 respectively). (A) 2 KJ (B) 102 K J (C) 92 K J (D) 92 KJ

Tardigrade Admin · Accepted Answer

According to the definition of successive ionization enthalpies.

M g_{(g)} + Δ_{i} H_{1} \to M g_{(g)}^{+} + e^{-};

Δ_{i} H_{1} = 735.76 K J m o l^{- 1}

M g_{(g)}^{+} + Δ_{i} H_{2} \to M g_{(g)}^{2 +} + e^{-};

Δ_{i} H_{2} = 1450.73 K J m o l^{- 1}

∴

Total amount of energy needed to convert

M g_{(g)}

atom into

M g^{2 +} (g) i o n = Δ_{i} H_{1} + Δ_{i} H_{2}

= 737.76 + 1450.73 K J m o l^{- 1}

24 m g o f M g = \frac{24}{1000} g = \frac{24}{1000 \times 24} m o l e = 1 0^{- 3} m o l e

∴

Amount of energy needed to ionize

1 0^{- 3}

mole of Mg vapours = 2188.49

\times

1 0^{- 3}

= 2.188 kJ ≈ 2 kJ

Q. The energy required to convert all the atoms of magnesium to magnesium ions present in 24 mg of magnesium vapours is (First and second ionization enthalpies of Mg are 737.76 and 1450.73KJmol−1 respectively).

2 KJ

102 K J

92 K J

92 KJ

Q. The energy required to convert all the atoms of magnesium to magnesium ions present in 24 mg of magnesium vapours is (First and second ionization enthalpies of Mg are 737.76 and $1450.73 K J m o l^{- 1}$ respectively).