This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.
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Here are the answers to the multiple-choice questions: 1. The weight of one molecule of CaCO₃ is Step 1: Calculate the molar mass of CaCO_3. Molar mass of CaCO_3 = Ca + C + 3 × O Molar mass of CaCO_3 = 40.08 + 12.01 + 3(16.00) = 40.08 + 12.01 + 48.00 = 100.09 g/mol Step 2: Calculate the weight of one molecule using Avogadro's number (6.022 × 10^23 molecules/mol). Weight of one molecule = Molar massAvogadro's number Weight of one molecule = 100.09 g/mol6.022 × 10^23 molecules/mol Weight of one molecule ≈ 1.66 × 10^-22 g The correct option is b) 1.66 × 10^-22 gm. 2. The gaseous hydrocarbon having formula CnH₂n+2 diffuses twice as quickly as sulphur dioxide. The molecular formula of hydrocarbon is Step 1: Apply Graham's Law of Diffusion. Graham's Law states that the ratio of the rates of diffusion of two gases is inversely proportional to the square root of the ratio of their molar masses: Rate_1Rate_2 = sqrt(Molar mass)_2Molar mass_1 Let the hydrocarbon be gas 1 and sulphur dioxide (SO_2) be gas 2. Given: Rate_hydrocarbon = 2 × Rate_SO_2, so Rate_hydrocarbonRate_SO_2 = 2. Molar mass of SO_2 = 32.07 (S) + 2 × 16.00 (O) = 64.07 g/mol. Step 2: Calculate the molar mass of the hydrocarbon. 2 = sqrt((64.07)/(Molar mass)_hydrocarbon) Squaring both sides: 4 = (64.07)/(Molar mass)_hydrocarbon Molar mass_hydrocarbon = (64.07)/(4) = 16.0175 g/mol Step 3: Determine the molecular formula of the hydrocarbon. The hydrocarbon has the formula C_nH_2n+2. Molar mass of C_nH_2n+2 = n(12.01) + (2n+2)(1.01) = 12.01n + 2.02n + 2.02 = 14.03n + 2.02. Set this equal to the calculated molar mass: 14.03n + 2.02 = 16.0175 14.03n = 16.0175 - 2.02 14.03n = 13.9975 n ≈ 1 For n=1, the formula is C_1H_2(1)+2 = CH_4. The molar mass of CH_4 = 12.01 + 4(1.01) = 16.05 g/mol, which matches our calculation. The correct option is d) CH_4. 3. The structure of NaCl is The correct option is b) Face centered cubic lattice. 4. Paste of lime in water is called The correct option is c) milk of lime. 5. Which one of the following elements is macro element? The correct option is a) Mg. 6. Which one of the following is amphoteric oxide? The correct option is b) ZnO. 7. The formula of ammonium carbamate formed during manufacture of urea is The correct option is b) NH_2COONH_4. 8. Hydrometallurgy is applied for the reduction of The correct option is c) Ag_2S. 9. White phosphorous reacts with caustic alkali to give The correct option is **c)