All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 575 of 686
- A. Rate of reaction
- B. Physical states of reactants and products.
- C. Conditions
- D. Both A & C
Explanation: Chemical equations involve the elements involved in a reaction, the number of molecules of the elements, the state symbols.
Correct answer: Both A & C- A. Chlorine
- B. Hydrogen
- C. Flourine
- D. Cadmium
Explanation: The number of isotopes of the following elements are: Chlorine 2 Hydrogen 3 Fluorine 1 Cadmium 11
Correct answer: Flourine- A. It is counting unit
- B. It is the gram atomic or gram formulae mass of a substance
- C. It contains 6.023 x 10^23 particles
- D. It contains different number of particles for different substances
Explanation: Option d is correct because moles represent a quantity of substance, and this quantity will differ for different substances due to their…
Correct answer: It contains different number of particles for different substances- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The balanced chemical equation is 3Mg+2NH3→Mg3N2+3H2 48 g of magnesium will react with (48×2×17)/(24×3)=22.67 g of ammonia.
Correct answer: Option A- A. 1 mg of C4H10
- B. 1 mg of N2
- C. 1 mg of Na
- D. 1 ml of H2O
Explanation: Following is the solution to this question:
Correct answer: 1 ml of H2O- A. 32 g
- B. 41.2 g
- C. 80
- D. 156 g
Explanation: Following is the solution to this question:To find the molecular mass of the alcohol, we can use the formula:Molecular mass = (Mass of…
Correct answer: 80- A. 0.1 mol and 0.3 mol
- B. 0.05 mol and 0.3 mol
- C. 0.05 mol and 0.15 mol
- D. 0.1 mol and 0.15 mol
Explanation: First, form a balanced equation of the reaction.KIO3 + 2 KI + 6 HCl → 3 ICl + 3 KCl + 3 H2OCalculate the moles of KI used Mass of KI =…
Correct answer: 0.05 mol and 0.15 mol- A. 68000 times
- B. 17000 times
- C. 34000 times
- D. 1700 times
Explanation: Mass of Hb compared to H/Molar mass of Helium 68000/4= 17000
Correct answer: 17000 times- A. 25 g of iodine
- B. 25 g atoms of oxygen
- C. 25 g moles of water
- D. 25 g of nitrogen gas
Explanation: Mass of I2 = 25 g mass of O atoms= 25 x 16= 400 g mass of H2O = 25 x 18= 450 g mass of N2 gas= 25 g So, H20 has the maximum mass.
Correct answer: 25 g moles of water- A. 2.24dm3
- B. 22.4dm3
- C. 112cm3
- D. 1.12 dm3
Explanation: No. Of moles (n) = mass/ M.mass=4.4/44 = 0.1 mole Volume = n x 22.414 dm3 = 0.1 x 22.414=2.24 dm3
Correct answer: 2.24dm3- A. It is counting unit
- B. It is the gram atomic or gram formula mass of a substance
- C. It contains 6.023 x 10^23 particles
- D. It contains different number of particles for different substances
Explanation: 1 mole of any substance contains equal No. of particle i.e. 6.02x1023
Correct answer: It contains different number of particles for different substances- A. H20
- B. C6H6
- C. H2O2
- D. NaCI
Explanation: Ionic compoundsdo not have molecule rather they have formula unit (Empirical formula) so they don't have molecular formula but have…
Correct answer: NaCI- A. Mg
- B. HCI
- C. Both are in stoichiometric amounts
- D. MgCl2
Explanation: If equal masses of reactants are given then the reactant whose larger molar mass is used in balance chemical equation is limiting reactant…
Correct answer: Mg- A. A limiting reactant is consumed at the end of reaction
- B. Actual yield is always greater than theoretical yield
- C. Stochiometric calculation can be only done if no side reaction happens
- D. The empirical formula and molecular formula of some of compounds are same
Explanation: Actual yield is always less than theoretical yield
Correct answer: Actual yield is always greater than theoretical yield- A. 1.008x1.661 x 10^-23 kg
- B. 1.008x1.661 x 10^-27kg
- C. 1.00
- D. 1.661 x 10^-27kg
Explanation: Explanation for this question will be added soon!
Correct answer: 1.008x1.661 x 10^-27kg- A. 1 mole
- B. 2 moles
- C. 0.5 moles
- D. 0.25 moles
Explanation: Explanation for this question will be added soon!
Correct answer: 0.5 moles- A. 100°C, 1 atm
- B. 298 K, I atm
- C. 273 K 760 mm Hg
- D. 0°C, 760 cm Hg
Explanation: Explanation for this question will be added soon!
Correct answer: 273 K 760 mm Hg- A. 2.24dm3
- B. 22.4dm3
- C. 11.02dm3
- D. 1.24dm3
Explanation: According to Avogadro's Law and the molar mass of oxygen (O₂), which is approximately 32 g/mol, 1 mole of oxygen gas occupies 22.4 dm³ at…
Correct answer: 11.02dm3- A. All the reactants are completely converted into products
- B. Reversible reaction occurs
- C. In calculations, law of conservation of mass and law of definite proportions are obeyed
- D. Side reaction occurs
Explanation: Correct answer is D. A side reaction, also known as a secondary reaction, is a chemical reaction that occurs simultaneously with the…
Correct answer: Side reaction occurs- A. 40 g
- B. 30 g
- C. 50 g
Explanation: Molar mass of Na= 23g/mo. Moles of Na= 23/23= 1 mole Sodium has one valence electron. Calcium has one valence electron per mole of sodium.
Correct answer: 40 g