Free MCQs & Online Quiz Practice for Exams

Q: Which gas occupies the largest volume at STP? (Entry test 2013)

A) 16g of CH₄

B) 32g of O₂

C) 4g of H₂

D) 28g of N₂

Q: A sample of carbon-12 has a mass of 3.0 g. Which expression gives the number of atoms in the sample? (Nₐ = Avogadro’s constant) (Entry test 2013)

A) 0.0030Nₐ

B) 0.25Nₐ

C) 3.0Nₐ

D) 4.0Nₐ

Q: How many molecules are present in 0.20 g of hydrogen gas? (Entry test 2013)

A) (0.20×1.008)×6.02x10²³

B) 0.20×2.016

C) (0.20×2.016)x6.02×10²³

D) (0.20×0.70)x6.02×10²³

Q: Choose the correct relation about the percent yield. It is equal to: (Entry test 2014)

A) (actual yield/theoretical yield)×100

B) (theoretical yield/actual yield)×100

C) (actual yield/theoretical yield)×10⁶

D) (actual yield/theoretical yield)×10³

Q: Which of the following contains maximum number of atoms? (Entry test 2015)

A) 6 mol of sulfur (S)

B) 2 mol of S₈

C) 5 mol of SO₂

D) 44.8 dm³ of CO₂ at STP

Q: The number of atoms in 18 g of H₂O are equal to: (Entry test 2015)

A) 6.02×10²³

B) 6.02×10²⁴

C) 1.806×10²⁴

D) 3.052×10²³

Q: Theoretical yield is always: (Entry test 2015)

A) Less than practical yield

B) Greater than actual yield

C) Both are equal

D) None of the above

Q: How many grams of Al₂O₃ will be obtained if 13.5 g of aluminum completely reacts with oxygen as 4Al + 3O₂ → 2Al₂O₃, (molar mass of AL=27g/mol) (Entry test 2015)

A) 25.5 g

B) 27.54 g

C) 54.27 g

D) 14.27 g

Q: What is the number of hydrogen atoms in 5 moles of water? (Entry test 2015)

A) 3.0115×10²⁴

B) 6.02×10²⁴

C) 6.02×10²³

D) 5.0×10²³

Q: Oxygen is prepared by the thermal decomposition of KClO₃: 2KClO₃ → 2KCl + 3O₂. How many moles of KClO₃ are required to prepare 6 moles of oxygen? (Entry test 2015)

A) 3.17 mol

B) 4.0 mol

C) 5.01 mol

D) 2 mol

Q: In the reaction N₂ + 3H₂ → 2NH₃, the limiting reagent is: (Entry test 2015)

A) N₂

B) H₂

C) Ammonia

D) None

Q: Mass of one molecule of oxygen is: (Entry test 2015)

A) 32 g

B) 16 g

C) (32/6.02)×10²³g

D) 32×6.02×10²³

Q: Cylinder A contains 4.6 g of C₂H₅OH and cylinder B has 3 g of C₂H₆. Which statement is correct? (Entry test 2016)

A) Both A and B have equal number of molecules

B) Cylinder A has greater number of molecules than cylinder B

C) Both cylinders have equal number of hydrogen atoms

D) Both a & c

Q: How many oxygen atoms are present in 278 g of hydrated ferrous sulfate (FeSO₄·7H₂O = 278 amu)? (Entry test 2016)

A) 6.023×10²³

B) 60×6.02×10²³

C) 2.408×10²⁴

D) 6.023×10²²

Q: 60 amu of carbon contains how many carbon atoms? (Entry test 2016)

A) 60

B) 60×6.02×10²³

C) 5×6.02×10²²

D) 5

Q: Which of the following samples contains the maximum number of atoms? (Entry test 2016)

A) 4 g of H₂

B) 28 g of N₂

C) 22.4 dm³ of CO₂ at STP

D) 1.5 mol of O₂

Q: In the reaction 2XeF₆ + SiO₂ → 2XeOF₄ + SiF₄, if 122.6 g of XeF₆ reacts with 60 g of SiO₂ to form products, select the limiting reagent and amount of SiF₄ formed? [XeF₆ = 245.3 amu, SiO₂ = 60 amu, SiF₄ = 104 amu] (Entry test 2016)

A) XeF₆, 26 g

B) SiO₂, 26 g

C) XeF₆, 52 g

D) SiO₂, 52 g

Q: In the manufacture of urea, CO₂ + 2NH₃ → NH₂COONH₄. If 22.0 g of CO₂ reacts with 34 g of amonia to form ammonium carbonate, the reaction is taken as, irreversible and go to completion. Identify the limiting reagent and the amount of caromate formed: (Entry test 2016)

A) CO₂ 78g

B) NH₃ 78g

C) CO₂ 39g

D) NH₃ 39g

Q: What volume is required for complete combustion of 5 cm³ of C₂H₄ and 5 cm³ of C₂H₄ under same conditions? (Entry test 2016)

A) 5 cm³

B) 10 cm³

C) 25 cm³

D) 15 cm³

Q: DDT is used as an insecticide; its molar mass is 354.5 g/mol. If it contains 47.4% carbon, how many carbon atoms are there per molecule? (Entry test 2016)

A) 10

B) 12

C) 14

D) 16