For a spontaneous endothermic process at constant pressure,which of the following is true?

In an isolated system,find the condition for a spontaneous reaction.

Predict in which of the following,entropy increases or decreases:
$(i)$ $A$ liquid crystallizes into a solid.
$(ii)$ Temperature of a crystalline solid is raised from $0 \, K$ to $115 \, K$.
$(iii)$ $2NaHCO_{3(s)} \to Na_2CO_{3(s)} + CO_{2(g)} + H_2O_{(g)}$
$(iv)$ $H_{2(g)} \to 2H_{(g)}$

What is entropy?

One mole of ice is converted into water at $1 \ atm$ and $273 \ K$. The entropies of $H_2O_{(s)}$ and $H_2O_{(\ell)}$ are $38.2$ and $60.01 \ J \ mol^{-1} \ K^{-1}$ respectively. The enthalpy change for the conversion is ...... $J \ mol^{-1}$.

In which of the following processes is $\Delta S$ positive?