41. The color of the complex ion [CoCl4]2−[\text{CoCl}_4]^{2-}[CoCl4​]2− is:

a) Blue
b) Green
c) Yellow
d) Pink
Answer: b) Green

42. The transition metal that forms a complex with ethylenediamine is:

a) Copper
b) Iron
c) Cobalt
d) Nickel
Answer: c) Cobalt

43. The common oxidation state of copper in its compounds is:

a) +1
b) +2
c) +3
d) +4
Answer: b) +2

44. The element that forms a brown solution in its +4 oxidation state is:

a) Chromium
b) Manganese
c) Iron
d) Copper
Answer: b) Manganese

45. The transition metal used in the production of hydrogen gas from hydrochloric acid is:

a) Zinc
b) Nickel
c) Platinum
d) Copper
Answer: d) Copper

46. The property of transition metals that makes them good catalysts is:

a) Their ability to form multiple oxidation states
b) Their low melting points
c) Their large atomic size
d) Their lack of magnetic properties
Answer: a) Their ability to form multiple oxidation states

47. The transition metal that forms a complex with ammonia and turns yellow when exposed to air is:

a) Iron
b) Copper
c) Cobalt
d) Nickel
Answer: b) Copper

48. The transition metal that exhibits magnetic properties due to unpaired electrons is:

a) Zinc
b) Copper
c) Silver
d) Gold
Answer: b) Copper

49. The property that is NOT typical of transition metals is:

a) Formation of colored compounds
b) High electrical conductivity
c) Formation of ionic bonds
d) High density
Answer: c) Formation of ionic bonds

50. The transition metal with the electron configuration [Kr] 5s^2 4d^7 is:

a) Silver
b) Rhodium
c) Palladium
d) Cobalt
Answer: b) Rhodium