Activity order is:
Co < Cr < Mn
The higher active element can reduce the lesser active one.
A is correct as Mn can reduce Cr
B is wrong as Co can’t reduce Cr
C is wrong as both Mn and Cr are getting oxidised.
B is wrong as both Co2+ and Cr3+ are getting reduced.
Answer: A
Chromium is less active than Manganese but more active than Cobalt. Which of the following reactions...
In which of the following unbalanced reactions does chromium undergo oxidation ? Cr3+ - Cr2+ More than one possible answer is shown o Cr3+ - Cr₂O72- Croq 2- Cr₂O72- Cr3+ - Cr
5. Which of the following metals can be oxidized by Co2 (aq)? (a) Chromium (b) Manganese (c) Nickel (d) Answers (a) and (b) (e) Answers (a), (b) and (c) 6. Which of the following compounds is/are soluble in water? (a) CuS (b) Pb(NOs)2 (c) ZnCO3 (d) Answers (a) and (b) (e) Answers (a), (b) and (c)
6) Of the choices below, which would be the best for the lining of a tank intended for use in storage of hydrochloric acid? A) copper B) zinc C) nickel D) iron E) tin 7) Which of these metals will be oxidized by the ions of cobalt? A) nickel B) tin C) iron D) copper E) silver 8) Which of these metals will be oxidized by the ions of aluminum? A) magnesium B) zinc C) chromium D) iron E) nickel...
A electrolytic cell similar to that shown in the figure above is constructed. The electronic device shown at the top of the figure is a power supply. One electrode compartment consists of a manganese strip placed in a 1.0 M Mn(NO3)2 solution, and the other has a cobalt strip placed in a 0.5 M Co2(SO4)3 solution. The overall cell reaction is: 3 Mn2+(aq) + 2 Co(s) 3 Mn(s) + 2 Co3+(aq) (a) Fill in the information necessary to complete the...
Four different metals (Cadmium, Cobalt, Chromium, and Sodium) were subjected to a beam of monochromatic light with a wavelength of 121.2 nm. Which metal will have an electron ejected with the highest velocity? a. Cd (νt = 9.86 x 1014 Hz) b. Co (νt = 1.21 x 1015 Hz) c. Cr (νt = 1.09 x 1015 Hz) d. Na (νt = 5.77 x 1014 Hz)
7) Why do hydrolysis reactions occur more readily in solution than dehydration reactions? A) Hydrolysis reactions increase G, or Gibbs free energy of the system, B) Hydrolysis reactions are endergonic and increase entropy of the system. C) Hydrolysis reactions are exergonic and decrease entropy of the system. D) Hydrolysis reactions are exergonic and increase entropy of the system. 8) How do cells use the ATP cycle illustrated in the figure? AAA W A) Cells use the cycle to recycle ADP...
How many grams of chromium metal will be deposited from a solution that contains Cr^3+ ions if a current of 1.01 A is applied for 40.2 minutes. Answer in______________ grams? How many grams of cobalt metal will be deposited from a solution that contains Co^2+ ions if a current of 0.517 A is applied for 40.5 minutes. Answer in_____________ grams? How many grams of cobalt metal will be deposited from a solution that contains Co^2+ ions if a current of...
Standard (reduction) potentials are given below for several half-reactions. Use them to answer the following. Mn2+ (aq) + 2e- → Mn(s) Cr3+(aq) + 3 e- → Cr(s) Sn2+(aq) + 2 e--> Sn(s) Cu2+ (aq) + 2 e → Cu(s) A13+ (aq) + 3 e- → Al(s) Co2+(aq) + 2 e- → Co(s) Cd2+ (aq) + 2 e- → Cd(s) Ered = -1.185 V Ered = -0.744 V Ered = -0.138 V = +0.342 V Ered = -1.662 V Ered =...
Standard (reduction) potentials are given below for several half-reactions. Use them to answer the following. Cd2+ (aq) + 2 e- → Cd(s) Mn2+(aq) + 2 e- → Mn(s) Cu2+ (aq) + 2 e- → Cu(s) Cr3+(aq) + 3 e- → Cr(s) Sn2+(aq) + 2 e- → Sn(s) A13+(aq) + 3 e- → Al(s) Co2+ (aq) + 2 e- → Co(s) Ered = -0.403 V Ered = -1.185 V Ered = +0.342 V Ered = -0.744 V Ered = -0.138 V...
5 If metal X is more active than metal Y (where both elements are in Group I), then indicate which of the following reactions would occur spontaneously. X + Y X +Y Occurs spontaneously? Y +X Y + X Occurs spontaneously? a in the reaction above, what is oxidized? b What is reduced? c What is the oxidizing agent? d What is the reducing agent?