NET, IAS, State-SET (KSET, WBSET, MPSET, etc.), GATE, CUET, Olympiads etc.: Chemistry MCQs (Practice_Test 3 of 31)
Get top class preparation for competitive exams right from your home: get questions, notes, tests, video lectures and more- for all subjects of your exam.
- For which one of the following reactions does the entropy of the system INCREASE?
- NH3 (g) + HCl (g) ⇾ NH4Cl (s)
- Ag + (aq) + Cl- (aq) ⇾ AgCl (s)
- 2H2 (g) + O2 (g) ⇾ 2H2O (g)
- NH3 (g) + H2O (l) ⇾ NH4 + (aq) + OH- (aq)
- 2H2O2 (l) ⇾ 2H2O (l) + O2 (g)
- Consider the following characteristics of chemical reactions
- spontaneity
- maximum amount of work that can be done
- speed
- The value of G for a chemical reaction under a given set of conditions provides information about:
- 1 only
- 2 only
- 3 only
- 1 and 2
- 1,2 and 3
- Consider the following standard reduction potentials, half-reaction Eo, V I3- (aq) + 2e________ > 3I- (aq) 0.53 Cr3 + (aq) + e ⇾ Cr2 + (aq) -0.41
- Calculate Go (in kJ) for the following reaction at 25oC.
- Cr2 + (aq) + I3- (aq) ⇾ Cr3 + (aq) + I- (aq)
- Consider the following reaction, 2SO2 (g) + O2 (g) ⟺ 2SO3 (g) , and the following thermochemical data, substance Gfo, kJ⟋mol, SO2 (g) -300.194, O2 (g) 0.0, SO3 (g) -371.06. Calculate the value of the equilibrium constant for this reaction at 25oC.
- N⟋A
- N⟋A
- N⟋A
- N⟋A
- For the dissociation of acetic acid in water at 25oC, CH3COOH (l) + H2O (l) ⟺ H3O + (aq) + CH3COO- (aq) , Ho = 284.3 kJ and So =-143.1 J K − 1. Calculate the value of Go (in kJ) for this reaction at equilibrium.
- N⟋A
- N⟋A
- N⟋A
- N⟋A
- Consider the carbonylation (i.e. … addition of CO) of methanol, CH3OH, to produce acetic acid, CH3COOH, in a closed system at constant temperature and pressure, CH3OH (g) + CO (g) ⟺ CH3COOH (g) , and the following data: Substance Hfo, kJ mol-1So, J mol-1 K − 1, CH3OH (g) -201240, CO (g) -110198, CH3COOH (g) -432283 If the initial concentration of CH3OH (g) is 1.5 M and the initial concentration of CO (g) is 2.0 M, what is the concentration (in M) of CH3OH (g) at equilibrium, at 298 K?
- N⟋A
- N⟋A
- N⟋A
- N⟋A
- For which of the following processes does the entropy of the system DECREASE?
- Melting of ice.
- Dissolving table salt in water.
- Decomposition of liquid hydrogen peroxide to produce liquid water and oxygen gas.
- Precipitation of silver chloride from a solution containing silver ions and chloride ions.
- The entropy of the system increases in all of the above processes.
- For a particular chemical reaction, the values for H and S are both positive. Which of the following statements is TRUE about this reaction?
- The reaction is spontaneous at any temperature.
- The reaction is not spontaneous at any temperature.
- The reaction is spontaneous when the temperature is high enough to overcome H.
- The reaction is spontaneous when the temperature is low enough to overcome H.
- The reaction is spontaneous when the temperature is low enough to overcome S.
- For the boiling of methanol, CH3OH (l) ⇾ CH3OH (g) , Ho =+ 38.0 kJ, and So =+ 113.0 J⟋K. Assume that methanol boils at a temperature at which the value of G is equal to zero. Using the values of Ho and So, calculate the temperature (in K) at which methanol boils.
- N⟋A
- N⟋A
- N⟋A
- N⟋A
- Which of the following reactions is unfavorable at low temperatures but becomes favorable as the temperature increases?
- 2 CO (g) + O2 (g) ⇾ CO2 (g) ; Ho =-566 kJ; So =-173 J⟋K
- 2 H2O (g) ⇾ 2 H2 (g) + O2 (g) ; Ho = 484 kJ; So = 90.0 J⟋K
- 2 N2O (g) ⇾ 2 N2 (g) + O2 (g) ; Ho =-164 kJ; So = 149 J⟋K
- PbCl2 (s) ⇾ Pb2 + (aq) + O2 (g) ; Ho = 23.4 kJ; So =-12.5 J⟋K
- The following reaction is spontaneous as written: Zn (s) + Cu2 + (aq) ⇾ Zn2 + (aq) + Cu (s) Which of the following statements is TRUE?
- Keq > 1 and Go = 0
- Keq > 1 and Go < 0
- Keq < 1 and Go < 0
- Keq > 1 and Go > 0
- Keq < 1 and Go = 0
- A spontaneous reaction ALWAYS occurs when:
- Ho < 0 and So < 0
- Ho > 0 and So < 0
- Ho < 0 and So > 0
- Ho > 0 and So = 0
- Ho > 0 and So > 0
- When a reaction is at equilibrium, which of the following statements is TRUE?
- G = Go
- ln Keq = 0
- Go = 0
- Q = 0
- G = 0