Acids, Bases and Salts Review Flashcards

Comprehensive flashcards generated from the complete lecture transcript on Acids, Bases, and Salts, including chemical properties, reactions, pH applications, and salt preparations.

What are the primary general properties of acids?

Acids are sour in taste, turn blue litmus red, and dissolve in water to release $H^+$ ions.

What are mineral acids and what are some examples of them?

Mineral acids are derived from inorganic compounds, mostly have a non-biological origin, dissolve well in water, and are mostly strong acids. Examples include $HNO_3$ and $H_2SO_4$.

What are organic acids and what are some examples of them?

Organic acids are derived from organic compounds, mostly have a biological origin, dissolve poorly in water, and are mostly weak acids. Examples include Citric acid and Vinegar.

How do strong acids and weak acids differ in terms of dissociation?

Strong acids completely dissociate into their ions in water (e.g., $HCl$, $H_2SO_4$, $HNO_3$), whereas weak acids partially dissociate into their ions in an aqueous solution or water (e.g., Acetic acid, Citric acid).

Which specific acids are found in vinegar, lemons/oranges, and tamarind/grapes?

Vinegar contains Acetic acid; lemons and oranges contain Citric acid; tamarind and grapes contain Tartaric acid.

Which acids are found in milk/yoghurt, apples/pears, and ant stings?

Milk and yoghurt contain Lactic acid; apples and pears contain Malic acid; ant stings contain Formic acid.

What acid is found in all citrus fruits?

Ascorbic acid (Vitamin C).

What products are formed when an acid reacts with a metal?

A metal salt and hydrogen gas ($\text{Acid} + \text{Metal} \rightarrow \text{Salt} + H_2$ gas, e.g., $2HCl + Zn \rightarrow ZnCl_2 + H_2$).

What products are formed when an acid reacts with a metal carbonate?

A salt, carbon dioxide, and water ($\text{Acid} + \text{Metal carbonate} \rightarrow \text{Salt} + CO_2 + H_2O$, e.g., $2HCl + Na_2CO_3 \rightarrow 2NaCl + CO_2 + H_2O$).

What products are formed when an acid reacts with a metal hydrogen carbonate?

A salt, carbon dioxide, and water ($\text{Acid} + \text{Metal hydrogen carbonate} \rightarrow \text{Salt} + CO_2 + H_2O$, e.g., $HCl + NaHCO_3 \rightarrow NaCl + H_2O + CO_2$).

What reaction occurs when an acid reacts with a metallic oxide?

They form a salt and water ($\text{Acid} + \text{Metal oxide} \rightarrow \text{Salt} + \text{Water}$, e.g., $2HCl + CuO \rightarrow CuCl_2 + H_2O$).

How do you test for the presence of $H_2$ gas and $CO_2$ gas?

$H_2$ gas gives a popping sound when a flame is brought near it. $CO_2$ gas turns lime water milky ($Ca(OH)_2 + CO_2 \rightarrow CaCO_3 + H_2O$).

Why can $H^+$ ions not exist alone in water, and what do they form?

$H^+$ ions combine with water molecules ($H_2O$) to form hydronium ions ($H_3O^+$).

Why must acid be added dropwise into water with constant stirring during dilution?

Dissolving acid in water is a highly exothermic reaction. Adding water to concentrated acid can cause the mixture to heat up, splash out, and cause burns; adding acid dropwise to water allows the generated heat to spread.

What is the definition of a base, and what is an alkali?

Bases are bitter in taste, turn red litmus to blue, and release $OH^-$ ions when dissolved in water. Bases that are soluble in water are called alkalis.

What reaction occurs between a base and a metal, and with which metals is it possible?

$\text{Base} + \text{Metal} \rightarrow \text{Salt} + H_2$ gas (e.g., $2NaOH + Zn \rightarrow Na_2ZnO_2 + H_2$). This reaction is possible only with reactive metals like sodium and potassium.

What are olfactory indicators, natural indicators, and synthetic indicators?

Olfactory indicators change odour in acidic or basic media (e.g., clove, vanilla, onion). Natural indicators include turmeric and litmus (obtained from lichen). Synthetic indicators include methyl orange and phenolphthalein.

What does 'p' in pH stand for, and what are the ranges on the pH scale?

The 'p' stands for 'potenz', a German word meaning power. On the pH scale, $1$ to $6$ is acidic, $7$ is neutral, and $8$ to $14$ is basic.

What pH levels define acid rain and the onset of tooth decay?

Acid rain occurs when the pH of rain water is less than $5.6$. Tooth decay begins below a pH of $5.6$.

What is the normal functioning pH range of the human body?

The human body functions within a pH range of $7.0$ to $7.8$.

What acid is present in a bee sting or nettle sting, and how is it neutralized?

They contain methanoic acid, which causes pain and irritation. It can be neutralized using a weak base like baking soda.

How is Sodium Hydroxide ($NaOH$) prepared, and what is the reaction equation?

It is prepared by the chlor-alkali process by electrolyzing brine: 2NaCl_{(aq)} + 2H_2O_{(l)} \rightarrow 2NaOH_{(aq)} + Cl_2_{(g)} + H_2_{(g)}.

How is Bleaching Powder ($CaOCl_2$) prepared?

It is prepared by reacting slaked lime with chlorine gas: $Ca(OH)_2 + Cl_2 \rightarrow CaOCl_2 + H_2O$.

What are the primary uses of Bleaching Powder?

1. Bleaching cotton and linen in textile industries, and wood pulp in paper industry. 2. Disinfectant for water. 3. Used as an oxidising agent.

What is the chemical formula, common name, and preparation equation of Baking Soda?

Chemical formula: $NaHCO_3$; Common name: Baking Soda. Preparation: $NaCl + H_2O + CO_2 + NH_3 \rightarrow NH_4Cl + NaHCO_3$.

What chemical reaction occurs when Baking Soda ($NaHCO_3$) is heated?

It decomposes to form sodium carbonate, water, and carbon dioxide: $2NaHCO_3 \rightarrow Na_2CO_3 + H_2O + CO_2$.

What is the formula and preparation method for Washing Soda?

Formula: $Na_2CO_3 \times 10H_2O$. It is prepared by the recrystallisation of sodium carbonate: $Na_2CO_3 + 10H_2O \rightarrow Na_2CO_3 \times 10H_2O$.

What is water of crystallization, and what are three standard examples?

It is the fixed number of water molecules present in one formula unit of a salt. Examples: $CuSO_4 \times 5H_2O$, $FeSO_4 \times 7H_2O$, and $CaSO_4 \times 2H_2O$.

How is Plaster of Paris prepared, and what is its chemical formula?

Plaster of Paris ($CaSO_4 \times \frac{1}{2}H_2O$) is prepared by heating gypsum ($CaSO_4 \times 2H_2O$) at $373\text{ K}$: $CaSO_4 \times 2H_2O \rightarrow CaSO_4 \times \frac{1}{2}H_2O + \frac{3}{2}H_2O$.