37. What is the oxidation number of C in (A) -2 (B C)+2 (D) 4 reaction takes pla
ID: 698427 • Letter: 3
Question
37. What is the oxidation number of C in (A) -2 (B C)+2 (D) 4 reaction takes place, what process occurs at the cathode? 3 ce'.(aq) + Cr(s) 3 Ces"(aq) + Cr(aq) formaldehyde, CH.0? What is the value of the quannum orbital? (A) 1 43. mumberI for a 5p 38. In a galvanic cell in which the following spontancous (B) 2 (C) 3 (D) 4 4. Which element has chemical properties most similar to (A) Reduction of Cr(aq) (B) Reduction of Ce (ag) (C) Oxidation of Cris) those of P? (A) N (B) A (C) S Which metal has the lowest melting point? (D) As 45. (D) Oxidation of Ce (aq) 46. Which gas-phase atoam has no umpaired electrons in its ground state? Which two half reactions, when coupled, will make a galvanic cell that will produce the largest voltage under standard conditions? 39. (A) Li (B) Be (C) B ) C 7. Which halogen atom has the greatest electron affinity? (A) F (B C (C) Br (D) I 11, Pb"(aq) + 2e- III. Ag.(aq) + e- Pb(s) Ag(s) E--0.13 E"-+0.80 V Which electronic transition in atomic hydrogen corresponds to the emission of visible light? 48. (A) (C) (B) (D) I and II 1 and andIV 111 and (C) n-3n-4 (D) n=3n-1 40. An electrolysis cell is operated for 3000 s using a current 4. Which species are linear? L NO (A) I only (C) Both I and II The peroxymonosulfate anion, HSO,, has (A) five sulfur-oxygen bonds and no oxygen-oxygen of 1.50 A. From which 1.0 M solution will the greatest mass of metal be deposited? (A) TINO (C) ZnCl (B) Pb(NO) (D) In(NO3)s (B) only (D) Neither I nor II 50. 41. The reduction of O2 to HO in acidic solution has a standard reduction potential of +1.23 V. What is the effect on the half-cell potential at 25 °C when the pH of the solution is increased by one unit? (B) four sulfur-oxygen bonds and one oxygen-oxygen (C) three sulfur-oxygen bonds and two oxygen-oxygen D) one sulfur-oxygen bond and four oxygen-oxygen 01g) + 4 H.(aq) + 4 e- 2H,0() bond. The half-cell potential decreases by 59 mV. (A) (B) The half-cell potential increases by 59 mV (C) The half ell potential decreases by 236 mV. (D) The half-cell potential increases by 236 mV. bonds. 51. Which statement about bonding is correct? (A) 42. Given the two standard reduction potentials below, what is the Kp of Ag:CrOs at 25 °C? A bond has cylindrical symmetry about the axis (B) A bond is twice as strong as a bond. (C) A double bond consists of two bonds (D) A bond results from the sideways overlap of E" +0.446 V Ag(aq) + Ag(s) (A) 864x1011 (C) 1.16x 10-1 E" = +0.799 V (B) 1.08 x 10 (D) 1.11 x 10- hybridized orbitals.Explanation / Answer
37. CH2O = x + 2(+1) + 1(-2) =0
x +2 -2= 0
Therefore x= 0, so oxidation state of carbon is zero.
38. At cathode always reduction takes place hence the reaction is reduction of Ce4+(aq) + e- ----------> Ce3+.
39. III and IV
Al becomes anode as its electrode potential is highly negative its oxidation is easy.
Ag becomes cathode as its electrode potential is highly positive which means its easily get reduction
E(cell) = E (cathode) -E(anode)
+0.80 - (-1.66) = +2.46V
40. According to Faraday's law of electrolysis the mass of metal deposited / plated is directly proportional to the equivalent mass of the metal. (equivalent mass=molar mass of the element / valency) Therefore
Among zn2+, Tl3+, Pb2+, In3+
the equivalent mass of Pb 2+ is more I,e 208/2= 104g hence mass of this metal deposited is greater among other metals
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