JEE Main 2015ChemistrySome Basic Concepts of ChemistryMediumMCQ

JEE Main 2015 — Some Basic Concepts of Chemistry Question with Solution

JEE Main 2015 (11 Apr Online)

Question

In the following reaction:

A+2B+3C⇌AB2C3
6.0 g of A, 6.0×1023  atoms of B and 0.036 mol of C reacted and formed 4.8 g of compound AB2C3. If the atomic mass of A  and C are 60 and 80 amu, respectively. What is the atomic mass of B in amu? (Avogadro number=6×1023)

Choose an option

Show full solutionCorrect option: D
Correct answer
D50 amu

Step-by-step explanation

A + 2 B + 3 C → AB 2 C 3 6 g 6 × 1 0 2 3 atoms 0.036 moles Moles 6 6 0 6 × 1 0 2 3 6 × 1 0 2 3 0.1 mole 1.0 mole 0.036 moles

0.11 ,1.02 ,0.0363; the least value is 0.012, i.e., C is the limiting reagent
0.036 moles of C provides 0.012 moles of AB2C3.

0.012 moles of AB2C3 weighs 4.8 g
1 mole of AB2C3 weighs 4.80.012=400 g mol-1
400=60+2B+3×80
B=50 amu

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About this question

This is a previous-year question from JEE Main 2015, covering the Some Basic Concepts of Chemistry chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.