Related InterviewSolutions

• Which of the following reactions is a synthesis reaction?A. When steam is passed over red hot coke, a mixture of carbon monoxide and hydrogen 15 fomed .B. Sodium reacts with water co form sodium hydroxide and hydrogen .C. When the milk of lime (calcium hydroxide) is added to hot sodium carbonate solution, sodium hydroxide is obtained and calcium carbonate separates out as mud.D. Stannic chloride is perpared by passing chlorine into molten tin.
• `Pb(NO_3)_2+Fe_2(SO_4)_3toFe(NO_3)_3+PbSO_4` Coefficients of lead sulphate and ferric nitrate in the balanced equation of above reaction areA. 3,4B. 3,3C. 3,2D. 2,3
• Sugar, on being treated with `H_2SO_4`, forms a black residue. If we observe the weights of sugar and the residue, we find a difference m weights. Why?
• Why is a physical change reversible?
• Why is the action of heat on iodine a physical change?
• Why is the burning of LPG a chemical change?
• The valency of a metal is 2 and its atomic weight is 24. What will be the molecular weight of its (a) sulphite (b) chloride (c ) chloride?
• Classify the following into physical and chemical changes. (i) Freezing of water (ii) Fermentation of alcohol (iii) Burning of coal (iv) Breaking of glass (v) Glowing of an electric bulb
• The valency of nitride ion is same as the valency of __________ ionA. FerricB. plumbicC. zincD. calcium
• Blue coloured `CuSO_4` is taken in two test tubes A and B. Zinc granules are added to test tube A and small iron piecces are added to test tube B. Explain the observations in each acse by giving reasons.