પ્રમાણભૂત સર્જન ઉષ્મા, kcal/mol of \(Ba ^{2+}\) માં કેટલી છે?
[આપેલ છે: \(SO _4^{2-}\) આયન \(( aq )\) ની પ્રમાણભૂત સર્જન ઉષ્મા \(=-216 kcal / mol\),
\(BaSO _4(s)\) ની પ્રમાણભૂત સ્ફટિકીકરણ ઉષ્મા
\(=-4.5 kcal / mol\), \(BaSO _4(s)\) ની પ્રમાણભૂત સર્જન ઉષ્મા \(=-349 kcal / mol \)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.