Answer: D. Sodium hydroxide
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Neutralization reaction is a type of double displacement reaction where an acid reacts with base to produce salt and water.
\(HCl+Na_2CO_3\rightarrow NaCl+H_2O+CO_2\)
Thus on reacting hydrochloric acid and sodium carbonate we get sodium chloride, water and carbon dioxide as products.
