which of the following reactions are double replacement reactions?\no naoh + hcl → hoh + nacl\no nacl → na +…

Brief Explanations:

A double - replacement reaction is a chemical reaction where the positive and negative ions of two ionic compounds exchange places. In the reaction $\text{NaOH}+\text{HCl}\rightarrow\text{HOH}+\text{NaCl}$, the sodium ion ($\text{Na}^+$) from $\text{NaOH}$ and the hydrogen ion ($\text{H}^+$) from $\text{HCl}$ exchange places. The reaction $\text{NaCl}\rightarrow\text{Na}+\text{Cl}_2$ is a decomposition reaction. The reaction $\text{Ca}+\text{S}\rightarrow\text{CaS}$ is a synthesis reaction. The reaction $\text{CH}_4+\text{O}_2\rightarrow\text{H}_2\text{O}+\text{CO}_2$ is a combustion reaction.

Answer:

$\text{NaOH}+\text{HCl}\rightarrow\text{HOH}+\text{NaCl}$