I believe the answers are
1) D
2) B
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Molarity is defined as the number of moles dissolved in 1 L of solution .2 mol of NaOH has been dissolved in a volume of 3 L.
we need to then find the number of NaOH moles dissolved in 1 L.
Molarity = number of moles / volume in L
Molarity = 2 mol / 3 L = 0.67 mol/L
Therefore molarity of NaOH - 0.67 M
NH3 and H2O and HF are all polar molecules
If Enthalpy is positive, the reaction is endothermic.
If Enthalpy is negative, the reaction is exothermic.
