The equivalent weight of Ba(OH)₂ is (given, atomic weight of Ba is 137·3)
85·7
137·3
154·3
171·3
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CDS-2 – 2018
The molar mass of Ba(OH)₂ is calculated as:
Atomic weight of Ba + 2 * (Atomic weight of O + Atomic weight of H)
= 137.3 + 2 * (16.0 + 1.0)
= 137.3 + 2 * 17.0
= 137.3 + 34.0
= 171.3 g/mol
Ba(OH)₂ is a strong base with two replaceable OH⁻ ions, so its acidity is 2.
Equivalent weight = Molar mass / Acidity = 171.3 g/mol / 2 = 85.65 g/equivalent.
Rounding to one decimal place gives 85.7 g/equivalent, which matches option A.