[SPM Chemistry MRSM 2019 P1 Q41 ] How to solve this question?

Let’s do elimination of options.

I. Burning methane involves: CH4 + 2O2 → CO2 + 2H2O. While CO2 is a greenhouse gas, it is relatively common for chemical plants to flare organic compounds and sent the CO2 emissions to the air, instead of keeping the methane as a volatile organic compound.

II. Since xylene is an organic compound, it cannot be dissolved in water (will form two layers). Therefore, option II should not be considered (Eliminate A and D)

III. Passing HCl through calcium carbonate. Since HCl is acidic (in aqueous form), reacting it with CaCO3 involves CaCO3 + 2HCl → CaCl2 + CO2 + H2O, whereby relatively harmless products are produced.

IV. Flowing the effluent into bromine water - Doesn’t really solve anything, as the bromine water containing the effluents cannot be simply discharged and have to be treated again.

Therefore, answer is B. I and III

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Ouhhh…Thank you very much! :grinning_face_with_smiling_eyes::+1::+1::+1: