Question

Example of reactuon of metal with acid chloride water

Answer 1

Explanation:

Salt solutions do not always have a pH of 7, however. Through a process known as hydrolysis, the ions produced when an acid and base combine may react with the water molecules to produce a solution that is slightly acidic or basic. We will not go into details here, but generally if a strong acid is mixed with a weak base there the resulting solution will be slightly acidic; if a strong base is mixed with a weak acid the solution will be slightly basic.

Example 14.5.1 : propionic acid + calcium hydroxide

Calcium propionate is used to inhibit the growth of molds in foods, tobacco, and some medicines. Write a balanced chemical equation for the reaction of aqueous propionic acid (CH3CH2CO2H) with aqueous calcium hydroxide [Ca(OH)2].

SOLUTION

Write the unbalanced equation.

This is a double displacement reaction, so the cations and anions swap to create the water and the salt.

CH3CH2CO2H(aq) + Ca(OH)2(aq)→(CH3CH2CO2)2Ca(aq) + H2O(l)

Balance the equation.

Because there are two OH− ions in the formula for Ca(OH)2, we need two moles of propionic acid, CH3CH2CO2H to provide H+ ions.

2CH3CH2CO2H(aq) + Ca(OH)2(aq)→(CH3CH2CO2)2Ca(aq) +2H2O(l)

Exercise 14.5.1

Write a balanced chemical equation for the reaction of solid barium hydroxide with dilute acetic acid.

Answer

Acids and Bases React with Metals

Acids react with most metals to form a salt and hydrogen gas. As discussed in Chapter 7, metals that are more active than acids can undergo a single diplacement reaction.

For example, zinc metal reacts with hydrochloric acid producing zinc chloride and hydrogen gas.

Zn(s)+2HCl(aq)→ZnCl2(aq)+H2(g)(14.5.4)

Bases react with certain metals like zinc or aluminum for example to also produce hydrogen gas. Sodium hydroxide reacts with zinc and water to form sodium zincate and hydrogen gas.

Zn(s)+2NaOH(aq)+2H2O(l)→Na2Zn(OH)4(aq)+H2(g).(14.5.5)

Contributors

Peggy Lawson (Oxbow Prairie Heights School). Funded by Saskatchewan Educational Technology Consortium.

Marisa Alviar-Agnew (Sacramento City College)