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3 things at home that contain bases
A household product “contains a base” when one of its ingredients either produces hydroxide ions in water (Arrhenius base) or accepts protons (Brønsted–Lowry base), resulting in a solution with \( \mathrm{pH > 7} \).
Operational meaning: If the active ingredient generates \(\mathrm{OH^-}\) in water or removes \(\mathrm{H^+}\) from acids, the product behaves as a base in aqueous solution.
Three common examples and the chemistry behind each
| Household item | Base-containing ingredient | Why it is basic (concept) | Representative equation in water |
|---|---|---|---|
| Baking soda | Sodium bicarbonate, \(\mathrm{NaHCO_3}\) (source of \(\mathrm{HCO_3^-}\)) | \(\mathrm{HCO_3^-}\) is a Brønsted–Lowry base that can accept \(\mathrm{H^+}\); in water it can also generate some \(\mathrm{OH^-}\) by reacting with \(\mathrm{H_2O}\). | \[ \mathrm{HCO_3^-(aq) + H_2O(l) \rightleftharpoons H_2CO_3(aq) + OH^-(aq)} \] |
| Household ammonia (glass cleaner / ammonia solution) | Ammonia, \(\mathrm{NH_3}\) (dissolved in water) | \(\mathrm{NH_3}\) is a weak Brønsted–Lowry base that accepts \(\mathrm{H^+}\) from water, producing \(\mathrm{OH^-}\). | \[ \mathrm{NH_3(aq) + H_2O(l) \rightleftharpoons NH_4^+(aq) + OH^-(aq)} \] |
| Milk of magnesia (antacid) | Magnesium hydroxide, \(\mathrm{Mg(OH)_2}\) | A metal hydroxide is an Arrhenius base because it supplies \(\mathrm{OH^-}\) in water (limited by its solubility, but still effective as an antacid). | \[ \mathrm{Mg(OH)_2(s) \rightleftharpoons Mg^{2+}(aq) + 2OH^-(aq)} \] |
Step-by-step justification using acid–base definitions
- Identify the active species in water. For ionic solids, write the dissolved ions (e.g., \(\mathrm{HCO_3^-}\)); for molecular bases, keep the molecule (e.g., \(\mathrm{NH_3}\)).
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Apply a definition.
- Arrhenius base: increases \(\mathrm{[OH^-]}\) in water.
- Brønsted–Lowry base: accepts \(\mathrm{H^+}\).
- Confirm the consequence for pH. Increasing \(\mathrm{[OH^-]}\) lowers \(\mathrm{[H_3O^+]}\) because \[ \mathrm{K_w = [H_3O^+][OH^-]} \] so a larger \(\mathrm{[OH^-]}\) implies a smaller \(\mathrm{[H_3O^+]}\), giving \( \mathrm{pH > 7} \).
Visualization: approximate positions on the pH scale
Practical ways to recognize bases in household products
- Ingredient clues: words like “hydroxide” (e.g., \(\mathrm{Mg(OH)_2}\), \(\mathrm{NaOH}\)), “ammonia,” or carbonate/bicarbonate salts often indicate basic behavior in water.
- Indicator test: pH paper or universal indicator shows \( \mathrm{pH > 7} \) for a basic solution.
- Neutralization behavior: bases react with acids to form salts and water; for example, hydroxide neutralization is represented by \[ \mathrm{H_3O^+(aq) + OH^-(aq) \rightarrow 2H_2O(l)} \]
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