Verified Solution • 2025–26 Session moderate

QJEEM20Chc4c6: JEE Main 2020 Chemistry - Class 12 JEEM20Chc4c6 Solution: The equation that is incorrect is :

The equation that is incorrect is :

Multiple Choice Options

  • A (Λm0)KCl−(Λm0)NaCl=(Λm0)KBr−(Λm0)NaBr{\left( {\Lambda _m^0} \right)_{KCl}} - {\left( {\Lambda _m^0} \right)_{NaCl}} = {\left( {\Lambda _m^0} \right)_{KBr}} - {\left( {\Lambda _m^0} \right)_{NaBr}}
  • B (Λm0)NaBr−(Λm0)NaI=(Λm0)KBr−(Λm0)NaBr{\left( {\Lambda _m^0} \right)_{NaBr}} - {\left( {\Lambda _m^0} \right)_{NaI}} = {\left( {\Lambda _m^0} \right)_{KBr}} - {\left( {\Lambda _m^0} \right)_{NaBr}}
  • C (Λm0)NaBr−(Λm0)NaCl=(Λm0)KBr−(Λm0)KCl{\left( {\Lambda _m^0} \right)_{NaBr}} - {\left( {\Lambda _m^0} \right)_{NaCl}} = {\left( {\Lambda _m^0} \right)_{KBr}} - {\left( {\Lambda _m^0} \right)_{KCl}}
  • D (Λm0)H2O=(Λm0)HCl+(Λm0)NaOH−(Λm0)NaCl{\left( {\Lambda _m^0} \right)_{{H_2}O}} = {\left( {\Lambda _m^0} \right)_{HCl}} + {\left( {\Lambda _m^0} \right)_{NaOH}} - {\left( {\Lambda _m^0} \right)_{NaCl}}

Step-by-Step Verified Solution

Left hand side :
(Λm0)NaBr−(Λm0)NaI{\left( {\Lambda _m^0} \right)_{NaBr}} - {\left( {\Lambda _m^0} \right)_{NaI}} = (Λm0)Br−−(Λm0)I−{\left( {\Lambda _m^0} \right)_{Br^-}} - {\left( {\Lambda _m^0} \right)_{I^-}} ....(1)

Right hand side :

(Λm0)KBr−(Λm0)NaBr{\left( {\Lambda _m^0} \right)_{KBr}} - {\left( {\Lambda _m^0} \right)_{NaBr}} = (Λm0)K+−(Λm0)Na+{\left( {\Lambda _m^0} \right)_{K^+}} - {\left( {\Lambda _m^0} \right)_{Na^+}} ....(2)

According to Kohlrausch's law option (B) is incorrect as (1) and (2) are not equal.

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