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 498 of 686
- A. HOI < HOBr < HOCl
- B. HCl < HBr < HI
- C. HIO4 < HBrO4 < HClO4
- D. All of the above are correct order
Explanation: In HOX with increase in electronegativity acid strength increases. In H - X acid strength increases with decrease in bond energies.
Correct answer: All of the above are correct order- A. Glucose
- B. NaCl
- C. BaCl2
- D. Al2(SO4)3
Explanation: The lowest vapour pressure would be observed in the case Al2SO4)3as it gives maximum no.
Correct answer: Al2(SO4)3- A. 4 g/l
- B. 8 g/l
- C. 12 g/l
- D. 14 g/l
Explanation: Isotonic solutions are those solutions, which have the same osmotic pressure, this means that they have the same concentrations.
Correct answer: 12 g/l- A. the entropy of mixing is zero
- B. the free energy of mixing is zero
- C. the free energy as well as the entropy of mixing are each zero.
- D. the enthalpy of mixing is zero
Explanation: When A and b form an ideal solution, ∆Hmax = 0.
Correct answer: the enthalpy of mixing is zero- A. Boiling points
- B. Vapour pressure at the same temperature
- C. Heat of vaporization
- D. Gaseous densities at the same temperature and pressure
Explanation: Gas density is defined as the mass of the gas occupying a certain volume at specified pressure and temperature.
Correct answer: Gaseous densities at the same temperature and pressure- A. Different boiling and different freezing points
- B. Same boiling and same freezing points
- C. Same freezing point but different boiling points
- D. Same boiling point but different freezing points
Explanation: The elevation in the boiling point and the depression in the freezing point are colligative properties and depend on the number of solute…
Correct answer: Same boiling and same freezing points- A. Lower
- B. Higher
- C. Same
- D. Can't be said
Explanation: In mixtures showing a positive deviation from Raoult's Law, the vapour pressure of the mixture is always higher than from an ideal mixture.
Correct answer: Lower- A. More than the vapour pressure of a solvent
- B. Less than the vapour pressure of solvent
- C. Equal to the vapour pressure of solvent
- D. None of these
Explanation: Addition of non-volatile solute always lowers the vapour pressure.
Correct answer: Less than the vapour pressure of solvent- A. Decimolar Al2(SO4)3
- B. Decimolar BaCl2
- C. Decimolar Na2SO4
- D. A solution obtained by mixing equal volumes and filtering
Explanation: Decimolar Al2(SO4)3 furnishes maximum number of ions.
Correct answer: Decimolar Al2(SO4)39950. The osmotic pressure of a solution can be accurately measured in the shortest possible time by:
- A. Berkeley and Hartley method
- B. Morse and Frazer method
- C. Pfeffer method
- D. None of the above
Explanation: It is more precise and takes minimum time.
Correct answer: Berkeley and Hartley method- A. Atmospheric pressure is low
- B. Temperature is low
- C. Atmospheric pressure is high
- D. None of the above
Explanation: The boiling occurs at lower temperature if atmospheric pressure is lower than 76 cm Hg.
Correct answer: Atmospheric pressure is low- A. Pure HCl only
- B. Pure water only
- C. Neither HCl nor water
- D. Both water and HCl in pure state
Explanation: An azeotrope is a mixture that exhibits the same concentration in the vapor phase and the liquid phase.
Correct answer: Neither HCl nor water- A. Molality
- B. Molarity
- C. Mole fraction
- D. All of these
Explanation: In case of dilute solution M=m∝ mole fraction.
Correct answer: Mole fraction- A. Ca(OH)2
- B. Na2CO3
- C. Na2SO4
- D. All of these
Explanation: All get dissolved with evolution of heat.
Correct answer: All of these9955. On mixing 10 mL of carbon tetrachloride with 10 mL of benzene the total volume of the solution is:
- A. > 20 mL
- B. < 20 mL
- C. = 20 mL
- D. Cannot be predicted
Explanation: No changes in interparticle forces as both are non-polar.
Correct answer: = 20 mL- A. 0.377
- B. 0.605
- C. 0.623
- D. 0.395
Explanation: By Raoult's law x_benzene = P/P° = 167/268 = 0.623, so x_solute = 0.377.
Correct answer: 0.605- A. NaCl
- B. Na2SO4
- C. Al2(SO4)3
- D. Al(NO3)3
Explanation: K3[Fe(CN)6]dissociates into 3K+ ions and one [Fe(CN)6]3- ion. So its Van't Hoff factor is 4.
Correct answer: Al(NO3)3- A. KCl
- B. MgCl2
- C. AlCl3
- D. Na3PO4
Explanation: Since As2S3 is a negatively charged colloidal sol, hence positively charged ion will cause its coagulation.
Correct answer: AlCl3- A. higher
- B. lower
- C. some times higher & some times lower
- D. none
Explanation: At the surface, a molecule is on one side surrounded by molecules of the same type and on the other side of another type.
Correct answer: higher- A. ∆H>0, ∆S<0
- B. ∆H<0, ∆S> 0
- C. ∆H<0 , ∆S< 0
- D. ∆ H>0,∆ S<0
Explanation: Both ∆H & ∆S are positive, while ∆G<0. which makes the adsorption process feasible.
Correct answer: ∆H>0, ∆S<0