If two similar capacitors of 4 μF each are connected in series the equivalent capacitance is:
💡 Explanation: For capacitors in series: 1/C = 1/4 + 1/4 = 2/4. Therefore C = 2 μF.
The speed of sound in air at room temperature is approximately:
💡 Explanation: The speed of sound in air at room temperature (20°C) is approximately 340 m/s.
A body of mass 0.5 kg moving with a velocity of 4 m/s has momentum equal to:
💡 Explanation: Momentum = mass × velocity = 0.5 × 4 = 2.0 Ns.
The velocity of sound is maximum in:
💡 Explanation: Sound travels fastest in solids like steel due to closely packed particles that transmit vibrations quickly.
Boyle's law states that at constant temperature:
💡 Explanation: Boyle's Law states that pressure and volume are inversely proportional at constant temperature: PV = constant.
Which of the following is the rate of change of velocity?
💡 Explanation: Acceleration is defined as the rate of change of velocity with respect to time.
Which row describes the type of bonding present in substances 1 and 2? Substance 1: Potassium chloride | Substance 2: Methane
💡 Explanation: Potassium chloride is an ionic compound. Methane (CH4) has covalent bonding between carbon and hydrogen atoms.
Which statement does NOT describe a property of a weak acid in solution?
💡 Explanation: A weak acid has a pH below 7 (acidic) not between 8 and 9 which would be basic.
Which does NOT describe a reaction at equilibrium?
💡 Explanation: At equilibrium Kc is constant not increasing. Kc only changes with temperature.
For which combination of acids and bases is the titration method of preparation suitable?
💡 Explanation: Titration requires both the acid and base to be soluble so they can react completely in solution.
Which does NOT increase the rate of reaction by affecting the number or nature of collisions?
💡 Explanation: A catalyst provides an alternative reaction pathway with lower activation energy but does not affect collision frequency or nature.
Which of the following changes is endothermic?
💡 Explanation: Decomposition of water requires energy input (endothermic) to break bonds between hydrogen and oxygen.
A mixture produces a gas both when it reacts with an acid and when it reacts with an alkali. Which ions are present?
💡 Explanation: Ammonium ions react with alkali to produce ammonia gas and carbonate ions react with acid to produce CO2.
In a Redox reaction electrons are transferred from:
💡 Explanation: In a redox reaction the reducing agent loses (donates) electrons to the oxidizing agent.
Soap-making process in industries is known as:
💡 Explanation: Saponification is the chemical process of making soap by reacting fats or oils with a strong base.