Question

2 the text describes the sequence of events that happens when acetic acid (vinegar) and sodium bicarbonate (baking soda) combine. what is the first thing that happens when these substances are combined? a carbonic acid decomposes rapidly to produce carbon dioxide and water. b carbon dioxide gas escapes and causes the solution to bubble and expand. c an acid - base reaction occurs, forming the salt sodium acetate and carbonic acid. d carbon dioxide gas gets trapped and expands to create a light, airy texture.

Explanation:

Step1: Analyze the reaction between acetic acid and sodium bicarbonate

When acetic acid (\(CH_3COOH\)) and sodium bicarbonate (\(NaHCO_3\)) react, it is an acid - base reaction. The general form of an acid - base reaction is \(acid+base
ightarrow salt + water+carbon - dioxide\) (in some cases). The chemical equation for the reaction between acetic acid and sodium bicarbonate is \(CH_3COOH+NaHCO_3 = CH_3COONa+H_2CO_3\). Here, \(CH_3COONa\) is the salt (sodium acetate) and \(H_2CO_3\) (carbonic acid) is formed first.

Step2: Analyze the decomposition of carbonic acid

Carbonic acid (\(H_2CO_3\)) is unstable and decomposes as \(H_2CO_3=H_2O + CO_2\uparrow\). But this decomposition happens after the formation of carbonic acid in the acid - base reaction.

Step3: Analyze the behavior of carbon dioxide

After the decomposition of carbonic acid, if the carbon dioxide is trapped (for example, in baking), it can create a light, airy texture. And the escape of carbon dioxide gas can cause the solution to bubble and expand. But these are subsequent steps after the initial acid - base reaction.

Answer:

C. An acid - base reaction occurs, forming the salt sodium acetate and carbonic acid.