Why is it not possible to use solid sodium hydroxide directly to make a standard NaOH
solution?

Sodium hydroxide is deliquescent (absorbs moisture from the atmosphere) solid. It cannot be weighed accurately. Therefore, it is not possible to prepare a standard solution of sodium hydroxide of accurately known concentration by weighing NaOH.

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :