Medium MCQ +4 / -1 PYQ · JEE Mains 2021

Choose the correct statement from the following :

  1. A The standard enthalpy of formation for alkali metal bromides becomes less negative on descending the group.
  2. B The low solubility of CsI in water is due to its high lattice enthalpy.
  3. C Among the alkali metal halides, LiF is least soluble in water. Correct answer
  4. D LiF has least negative standard enthalpy of formation among alkali metal fluorides.

Solution

a. Standard enthalpy of formation for alkali metal bromides becomes more negative on descending down the group.<br><br>b. In case of CsI, lattice energy is less, but Cs<sup>+</sup> is having less hydration enthalpy due to which it is less soluble in water.<br><br>c. For alkali metal fluorides, the solubility in water increases from lithium to caesium. LiF is least soluble in water.<br><br>d. Standard enthalpy of formation for LiF is most negative among alkali metal fluorides.

About this question

Subject: Chemistry · Chapter: s-Block Elements · Topic: Alkali Metals

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