Sovle this two question and the concept behind the question

69) option d and 70) option c

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69 - All of these.

69) When ionic compound dissolves in water, it dissociates into ions and these ions are solvated by water molecules. This is an exothermic process.

let's just suppose that we have NaCl as the ionic compound. As soon as we add this NaCl in water, the attractive forces between Na+ and Cl- starts weakening due to start of solvati...

The attractive forces starts weakening and the ions are hydrated. This process involves heat too!