Inorganic Chemistry & Acids-Bases — Part 1: 40 MCQs with Explanations

Longest chain containing carboxyl group has 3 carbons (propanoic acid) with methyl at carbon 2: 2-methylpropanoic acid.

In rock salt structure, each Na⁺ is surrounded octahedrally by 6 Cl⁻ ions.

HCOOH is methanoic acid (formic acid), the simplest carboxylic acid.

Acetic acid (CH₃COOH) has highest solubility due to strong hydrogen bonding and partial ionization in water.

Adding H⁺ to HPO₄²⁻ gives H₂PO₄⁻, its conjugate acid.

Tartaric acid has two chiral centers. It has three stereoisomers: (+), (-), and meso form (internally compensated).

Density order: Li(0.53) < K(0.86) < Na(0.97) < Rb(1.53) < Cs(1.88) g/cm³. Among options, Rb has highest density.

For weak acid, some energy is consumed in ionization, so less heat is evolved: |ΔH| < 57.1 kJ/mol.

Phenol (carbolic acid) and its derivatives are used as antiseptics and disinfectants.

Vitamin C (ascorbic acid) is water-soluble. Vitamins A, D, E, K are fat-soluble.

Vinegar contains 5-8% acetic acid (CH₃COOH), responsible for its sour taste.

Aspirin (acetylsalicylic acid) is a common analgesic (pain reliever) and antipyretic.

Scurvy is caused by deficiency of vitamin C (ascorbic acid), leading to bleeding gums and poor wound healing.

Acetylene (ethyne) mixed with oxygen produces oxy-acetylene flame used in welding and cutting metals.

Soaps are sodium or potassium salts of fatty acids obtained by saponification of fats/oils (triglycerides).

Sodium bicarbonate (NaHCO₃) neutralizes excess stomach acid and is used as antacid.

NH₃ deviates most due to strong intermolecular forces (hydrogen bonding) and relatively large molecular size compared to noble gases and N₂.

Saponification is the alkaline hydrolysis of esters (fats/oils) to produce soap (sodium salts of fatty acids) and glycerol.

Removing H⁺ from H₂PO₄⁻ gives HPO₄²⁻, which is its conjugate base.

Iron (Fe) with promoters (Al₂O₃, K₂O) is used as catalyst in Haber process for ammonia synthesis: N₂ + 3H₂ ⇌ 2NH₃.

Lithium has the highest density among alkali metals? Actually, density increases down the group: Li (0.534) < Na (0.968) < K (0.89) < Rb (1.532) g/cm³. Wait, potassium has lower density than sodium due to abnormal increase in atomic size. Correct order: Li < K < Na < Rb < Cs. So Rb has highest density among options.

For weak acid-strong base neutralization, heat evolved is less than 57.1 kJ/mol because some energy is used to ionize the weak acid (HCN ⇌ H⁺ + CN⁻ is endothermic).

Group 2 elements (Be, Mg, Ca, Sr, Ba, Ra) are known as alkaline earth metals. Li, Na, and K belong to Group 1 (Alkali metals).

Reactivity of alkali metals increases down the group due to decreasing ionization energy and increasing atomic size. Francium, being at the bottom, is theoretically the most reactive, though it is radioactive and rare.

Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase. Examples: camphor, naphthalene, dry ice.

Alkali metals like Potassium are highly reactive. They readily react with oxygen and moisture in the air, and explosively with water. Storing them under kerosene isolates them from air and moisture.

Group 17 (VII-A) elements (F, Cl, Br, I, At) are known as halogens (Greek: 'salt-formers') because they react with metals to form salts.

Metals above hydrogen in the reactivity series displace hydrogen from dilute acids. Copper (Cu) is below hydrogen in the reactivity series and cannot displace H⁺ ions from acids, so no hydrogen gas is evolved.

Rust is a general term for hydrated iron(III) oxide. Its chemical formula is approximately Fe₂O₃·xH₂O. The 'x' represents a variable amount of water of hydration.

Gases with strong intermolecular forces (like hydrogen bonding) and high polarizability deviate most from ideal behavior. NH₃ (ammonia) exhibits hydrogen bonding, causing it to deviate significantly at room temperature.

Optical activity is shown by chiral molecules (having no plane of symmetry and a non-superimposable mirror image). Lactic acid (CH₃-CHOH-COOH) has a chiral carbon (the central carbon attached to four different groups: H, OH, CH₃, COOH).

Bauxite is the principal ore of aluminum. It is a mixture of hydrated aluminum oxides, primarily gibbsite (Al(OH)₃), boehmite (γ-AlO(OH)), and diaspore (α-AlO(OH)).

Pascal (Pa = N/m²) is a derived unit for pressure. Meter, second, and kilogram are base SI units.

E = E° - (RT/nF) ln Q = E° - (0.059/n) log Q at 298 K (using log base 10).

Oxygen constitutes ~46.6% by mass of Earth's crust, mostly in silicates and oxides.

Scandium (Z=21) is d-block element (first transition series). p-block includes Groups 13-18.

Borax (Na₂B₄O₇) forms colored metaborates with transition metal oxides when heated in flame, used in qualitative analysis.

Al₂O₃ reacts with both acids and bases: Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O; Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O.

Aluminum is most abundant metal (~8.1% by mass), occurring mainly as bauxite (Al₂O₃·2H₂O).

Cl₂ + H₂O ⇌ HCl + HOCl. Hypochlorous acid (HOCl) decomposes to release nascent oxygen which bleaches colored substances.