Answer: An acid can be prepared by direct combination of element , dissolving some acidic anhydride in water or by displacement of a weaker or non volatile acids from its salt by a stronger or less volatile acid.
Step-by-step explanation:
1. acid + base ⟶ water + salt.
2. HCl(aq) + KOH(aq) ⟶ H 2O(ℓ) + KCl(aq)
3. HCl(aq) + Mg(OH) 2(aq) ⟶ 2 H 2O(ℓ) + MgCl 2(aq)
4. HCl(aq) + NH3(aq) ⟶ NH4Cl(aq)