The actual amount of CaO obtained on thermal decomposition of 25g of CaCO₃ is 12g. What is the approximate percentage yield? (Molar mass of CaCO₃ = 100, Molar mass of CaO = 56) CaCO₃ → CaO + CO₂
Correct answer: C. 86 %
- A. 50 %
- B. 60 %
- C. 86 %
- D. 90 %
Explanation
From the equation, 100 g of CaCO3 gives 56 g of CaO, so 25 g should give 14 g, which is the theoretical yield. The percentage yield is 12 divided by 14, multiplied by 100, which is about 86 percent. Dividing 12 by 25 instead gives 48 percent, close to the 50 percent distractor.
This question appeared on the UHS MDCAT 2026 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Theoretical and Percentage Yield
Theoretical yield is the maximum product predicted from a balanced equation and the amount of limiting reactant. Work includes identifying the limiting reagent, comparing theoretical and actual yield, and calculating percentage yield using stoichiometric mole relationships.
Practise Fundamental Concepts of Chemistry
898 free Fundamental Concepts of Chemistry MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Theoretical and Percentage Yield questions
A sample containing aluminum weighing 10.0g yielded 2.0g of aluminum sulphide. What is the percentage of aluminum (atomic mass 27.0) in the sample? Sulphur (atomic mass 32.0) =
Stoichiometric calculation based on chemical equation provides us intimation about :
A researcher has prepared a sample of 1-bromopropane from 10g of 1-propanol. After purification he had made 12g of product. Which of the following is percentage yield?
If actual yield and theoretical yield are 20g and 25g respectively, what will be the % yield?
The efficiency of chemical reactions can be checked by calculating its _ yield.