Question

1. multiple choice:

which of the following household substances is most likely to be basic?
a. lemon juice
b. vinegar
c. baking soda
d. orange juice

1. short answer:

describe what happens to the ph of a solution when an acid is added to water.

1. application:

you spill some vinegar (acid) on a counter. what household item could you use to
neutralize it?

1. challenge:

explain why strong acids and weak acids can have very different effects even if they
have the same concentration.

Explanation:

• For question 7: Baking soda (\(NaHCO_3\)) is a basic substance. Lemon juice, vinegar, and orange juice are acidic.
• For question 8: When an acid is added to water, it dissociates and releases \(H^+\) ions. According to the pH formula \(pH=-\log[H^+]\), an increase in \(H^+\) ion concentration leads to a decrease in pH.
• For question 9: Baking soda (\(NaHCO_3\)) can react with the acid (vinegar, which has acetic acid \(CH_3COOH\)). The reaction is \(CH_3COOH + NaHCO_3=CH_3COONa + H_2O+CO_2\uparrow\). Baking soda is a base - like substance (a salt of a weak acid and a strong base) and can neutralize the acid.
• For question 10: The effect of an acid depends on its degree of dissociation. Strong acids dissociate completely (\(HA

ightarrow H^++A^-\)), while weak acids dissociate partially (\(HA
ightleftharpoons H^++A^-\)). Even if they have the same concentration, the concentration of \(H^+\) ions (which determines the acidic effect) is different. For example, if we have a 1M solution of HCl (strong acid, \(HCl
ightarrow H^++Cl^-\), \( [H^+]=1M\)) and a 1M solution of \(CH_3COOH\) (weak acid, \( [H^+]\ll1M\) due to partial dissociation).

Answer:

1. C. Baking soda
2. The pH of the solution decreases.
3. Baking soda.
4. The effect of an acid depends on its degree of dissociation (strong acids dissociate completely, weak acids - partially), so even with the same concentration, \(H^+\) ion concentrations (and thus effects) differ.