Some Chemical Reactions MCQs with Answers

Heat of neutralization of strong acid by strong base is constant value because ?

• A.Only H⁺ + OH⁻ reaction occurs
• B.Salt formation is always exothermic
• C.Both acid and base are fully ionized
• D.Water acts as a catalyst

At the start of a reaction, the instantaneous rate is _?

• A.High
• B.Low
• C.Constant
• D.Zero

Iodine dissolves in water in the presence of KI due to formation of which of the following species?

• A.I⁻
• B.I₂
• C.I₃⁻
• D.IO₃⁻

Which type of the following chemical equation is? CaO + CO2 → CaCO3

• A.Combination reaction
• B.Decomposition reaction
• C.Displacement reaction
• D.Double displacement reaction

For NaOH + HCl → NaCl + H₂O, the change in enthalpy is _?

• A.Heat of solution
• B.Heat of formation
• C.Heat of combustion
• D.Heat of neutralization

Ignition of Fe(OH)₃ to give Fe₂O₃ is called?

• A.Calcination
• B.Oxidation
• C.Dehydration
• D.Roasting

The burning of substances in air with the release of a large amount of heat and light energy is called _?

• A.Combustion
• B.Oxidation
• C.Evaporation
• D.Sublimation

50g of Mg is burned with 32g of oxygen to form MgO. The amount of excess reagent left is?

• A.No excess reagent
• B.2g O₂
• C.18g Mg
• D.2g Mg

When ethanol is taken in excess and temperature is kept at 140°C, on dehydration with conc. H₂SO₄, it gives a molecule of?

• A.Ethene
• B.Ethane
• C.Ether
• D.Ethanoic acid

Boiling of an egg is a _?

• A.Physical change
• B.Chemical change
• C.Reversible change
• D.None of these