Explanation

To get max Cr from Cr₂O₃, use the mass fraction of Cr in Cr₂O₃.

Molar mass Cr₂O₃ = 2(52) + 3(16) = 104 + 48 = 152 g/mol

Mass of Cr in 1 mol = 2(52) = 104 g

So Cr mass = 76g × (104/152) = 76 × 0.684 = 52g

Last verified on 11-04-2026

Explanation

• Coal, petroleum, and natural gas are fossil fuels formed from ancient organic matter.
• Hydrogen is a clean fuel, not formed from fossilized remains.
• It is considered a future energy source due to its high efficiency and low pollution.

Last verified on 11-04-2026

Explanation

• Electrolysis of concentrated aqueous sodium chloride (brine) involves breaking down compounds using electricity.
• Inert electrodes do not take part in the reaction.
• At the negative electrode (cathode), reduction occurs.
• Hydrogen ions are reduced instead of sodium ions in aqueous solution.
• This produces hydrogen gas at the cathode.

Last verified on 11-04-2026

Explanation

• In thermodynamics, state functions depend only on initial and final states.
• They do not depend on the path taken.
• Examples include internal energy, enthalpy, and entropy.
• Work done depends on the path of the process.
• Therefore, it is not a state function.

Last verified on 11-04-2026

Explanation

• A salt and water mixture is a homogeneous solution.
• To separate both components, we need a method that recovers water and salt separately.
• Some methods only recover one component.
• Proper separation depends on physical properties like boiling point.
• Distillation is used for complete separation of both substances.

Last verified on 11-04-2026

Explanation

• Enzymes work best at an optimum temperature.
• Temperature changes affect enzyme activity and shape.
• High temperature can damage enzyme structure.
• This reduces the enzyme’s ability to function properly.
• Enzymes are sensitive biological catalysts.

Last verified on 11-04-2026

Explanation

The human urinary system functions as a sequence of organs that filter blood and eliminate waste in a specific order: 

1. Kidney: The starting point where blood is filtered and urine is formed.
2. Ureter: Narrow, tubular structures that transport the formed urine from the kidneys down to the bladder.
3. Urinary Bladder: A muscular sac in the pelvic cavity that acts as a temporary storage reservoir for urine.
4. Urethra: The final canal-shaped tube through which urine is expelled from the body to the exterior.

Last verified on 11-04-2026

Explanation

• Snakes normally control the population of primary consumers.
• When snakes decrease, predation pressure reduces.
• As a result, primary consumers (like rodents, insects) increase.
• This can disturb ecological balance in the desert ecosystem.

Last verified on 11-04-2026

Explanation

• This condition is caused by nondisjunction during meiosis.
• Homologous chromosomes fail to separate properly in meiosis I (or sister chromatids in meiosis II).
• As a result, one gamete gets an extra chromosome.
• After fertilization, this leads to trisomy 21 (Down syndrome).

Last verified on 11-04-2026

Explanation

• Lamarckism is an early evolutionary theory proposed by Jean-Baptiste Lamarck.
• It states that organs become stronger if used and weaker if not used.
• These acquired characteristics were believed to be passed to offspring
• For example, stretching of giraffe neck over generations.
• Hence, it is based on use and disuse of organs.

Last verified on 12-04-2026