JEE Main20209 Jan 2020Evening ShiftChemistryClassification of Elements and Periodicity in PropertiesActual
The first and second ionisation enthalpies of a metal are 496 and 4560 k J m o l - 1 , respectively. How many moles of H C l and H 2 S O 4 , respectively, will be needed to react completely with 1 mole of the metal hydroxide?
Options
- A1 and 1
- B2 and 0.5
- C1 and 2
- D1 and 0.5
Correct answer
D. 1 and 0.5
Step-by-step solution
Ionization Enthalpy values indicate that the metal belongs to I st group, since the second ionization enthalpy is very high. (Q - only one valence electron) Metal hydroxide will be of the type, MOH . MOH 1   mol + HCl 1   mol → MCl + H 2 O MOH + 1 2 H 2 SO 4 → 1 2 M 2 SO 4 + H 2 O ( 1 mol ) 1 2 mol So, one mole of HCl is required to react with one mole of MOH . So, 1 2 mole of H 2 SO 4 is required to react with one mole of MOH .