Post-UTME Chemistry 2010 Objective — Question 1
Question 1 of 10 from the Post-UTME Screening (Post-UTME) Chemistry 2010 Objective paper, with the correct answer and a full explanation.
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How many grams of HBr would exactly be required to react with 2g of propyne? (C=12, H=1, Br=80)
- A. 4.1gCorrect
- B. 6.1g
- C. 10.1g
- D. 8.1g
Explanation
Molar mass of propyne (C3H4)=40g/mol; moles=2/40=0.05mol. CH≡CCH3+HBr→CH2=CBrCH3 is 1:1, so 0.05mol HBr needed. Molar mass HBr=81; mass=0.05×81≈4.1g.
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