ICSE Questions Set in Previous Years

Question 1Name a gas which reduces hot copper (II) oxide to copper.

Question 2Write correctly a balanced equation for the following 'word' equation :Red lead ⟶ lead monoxide + oxygen

Question 3Name a gas which burns in air or oxygen forming H2O.

Question 4Name a gas used along with acetylene for welding and cutting metals.

Question 5Write correctly the balanced equation for the following :When red lead, Pb3O4 is heated.

Question 6Write correctly balanced equations in the following cases :(a) When lead (II) oxide (PbO2) is heated.(b) When phosphorous is burnt in a jar...

Question 7Name a gas which reduces hot copper (II) oxide to copper.

Question 8Name the products formed when a candle burns in oxygen.

Question 9Give a reason for the following :Like oxygen, nitrous oxide (N2O) also supports combustion. A glowing splint introduced into a jar of N2O,...

Question 10Name a non-metallic element which forms an acidic and a neutral oxide.

Question 11Name a non-metallic oxide which is a reducing agent.

Question 12Name (formula not acceptable) the gas produced in the following reaction: Burning of sulphur.

Question 13Explain why chlorine turns moist starch iodide paper blue-black.

Question 14State three tests by which you could identify a gas as being chlorine.

Question 15State what you observe when a piece of moist blue litmus paper is placed in a gas jar of chlorine.

Question 16For the elements sodium and phosphorous, state the following(a) the formula of the chloride of each element,(b) the physical state of each...

Question 17Describe the two colour changes that take place when moist blue litmus is placed in a gas jar of chlorine. What are these colour changes...

Question 18Write correctly a balanced equation for the following 'word equation':Calcium carbonate + Hydrochloric acid ⟶ Calcium chloride + water +...

Question 19In each case, describe one chemical test applied to the following substances, which would enable you to distinguish between them : carbon...

Question 20Give reasons for : 'It is dangerous to sleep in a closed room in which a coal fire is burning'.

Question 21Give the name of an acid salt found in 'Health Salts'.

Question 22Name two important processes which generate or release carbon dioxide into the atmosphere.

Question 23Name two processes which remove carbon dioxide from the atmosphere.

Question 24Explain the following :A white crust forms on the surface of lime water that has been exposed to the atmosphere.

Question 25Give the biological importance of carbon dioxide dissolved in water.

Question 26State your observations and give balanced equations of the reactions when carbon dioxide is passed through clear lime water (a) for a...

Question 27XCl2 is the chloride of a metal X. Write down the formula of the sulphate and the hydroxide of the metal X.

Question 28Complete the following 'word' equations. Write the words 'No reaction' if none occurs.(a) magnesium + copper sulphate ⟶(b) iron (II)...

Question 29Write the equation for the following and state whether it is a decomposition reaction : The action of heat on lead nitrate.

Question 30What are the constituent units of crystals of :(a) Iodine(b) Sodium chloride

Question 31(a) What is meant by the term 'atomicity of a gas'?(b) Name a gas that is diatomic.

Question 32Name a common substance that exists in all the three states of matter.

Question 33Give an example of an endothermic reaction.

Question 34An element X is trivalent. Write the balanced equation for the combustion of X in oxygen.

Question 35In which of the following four substances will there be :(a) increase in weight(b) decrease in weight(c) no change in weight, when exposed...

Question 36'When stating the volume of a gas, the pressure and temperature should also be given'. Why ?

Question 37Define or state :(a) Absolute temperature(b) Boyle's law(c) Charles' law

Question 38A gas occupies 760 cm3 at 27°C and 70 cm of Hg. What will be its volume at STP?

Question 39At 0°C and 760 mm Hg pressure, a gas occupies a volume of 100 cm3. The Kelvin temperature (Absolute temperature) of the gas is increased...

Question 40The pressure of one mole of gas at STP is doubled and the temperature is raised to 546 K. What is the final volume of the gas ? [one mole...

Question 41It is possible to change the temperature and pressure of a fixed mass of gas without changing it's volume. Give reasons for your answer.

Question 42Complete the following equations in words and then write the balanced molecular equation in each case.(a) Zinc nitrate + sodium carbonate...

Question 43Give one reason why magnetizing a piece of steel is a physical change.

Question 44Name a homogeneous mixture of :(a) a liquid and a solid(b) two liquids

Question 45If the formula of the nitride of a metal X is XN, what is the formula of(i) it's sulphate(ii) it's hydroxide.

Question 46What is the valency of nitrogen in(a) NO(b) N2O(c) NO2

Question 47Name a non-metallic element, which :(a) is liquid at ordinary temperature(b) is a conductor of electricity

Question 48Name a metal oxide which is yellow in colour.

Question 49Name the process of change of state by which napthalene changes into vapour. Name an element that can undergo the same change of state.

Question 50Dilute hydrochloric acid is added first to a mixture of iron and sulphur and then to a compound formed by iron and sulphur. Name the gases...

Question 51State whether the following conversations are examples of oxidation or reduction :(a) Na ⟶ Na+ + e-(b) PbO2 ⟶ PbSO4

Question 52Complete the following equations and state in each case if the reaction represents oxidation or reduction :(a) Fe2+ ⟶ Fe3+(b) Cl- ⟶ Cl(c)...

Question 53Reactions can be classified as follows :Direct combination, decomposition, simple displacement, double decomposition, redox...

Question 54Express Kelvin Zero in °C.

Question 55Study the reaction scheme below and then answer (a), (b) and (c) which follow :(a) Give the chemical name and formula of (i) marble (ii)...