The pair of electrolytes that posses same value for the constant (A) in the Debye-Huckel-Onsager equation, _ m = _ m ^ -A C is

Step-by-step solution

_ m = _ m ^ -A C Out of all the given pairs, the pair having same (similar) charges will possess the same value of A . Here, MgSO ₄ and Na ₂ SO ₄ Mg ²⁺ and Na ⁺ NH ₄ Cl and NaBr NH ₄⁺ and Na ⁺ NaBr and MgSO ₄ Na ⁺ and Mg ²⁺ NaCl and CaCl ₂ Na ⁺ and Ca ²⁺ So, only in NH ₄ Cl and NaBr , the charge is same on both the cations and hence, there will have same value of A .