Assertion (A): Silver chloride turns grey when kept in sunlight. Reason (R): Silver chloride undergoes a decomposition reaction by sunlight. MCQ with Answer and Explanation
Assertion (A): Silver chloride turns grey when kept in sunlight. Reason (R): Silver chloride undergoes a decomposition reaction by sunlight.
A. A is true but R is false.
B. A is false but R is true.
C. Both A and R are true and R is the correct explanation of A.
D. Both A and R are true but R is NOT the correct explanation of A.
Answer: Option C
Solution (By JKSSB Mock Tests)
When exposed to sunlight, silver chloride (AgCl) undergoes photolytic decomposition to form silver metal (which is grey) and chlorine gas. The equation is 2AgCl(s) + sunlight → 2Ag(s) + Cl₂(g). Both statements are correct, and the decomposition reaction perfectly explains the color change observed.
Explanation:
A catalyst does not initiate a reaction; it only changes the rate of a reaction that is already thermodynamically feasible. It provides an alternative pathway with lower activation energy. It does not change the overall enthalpy (ΔH) or the equilibrium position, and it is recovered unchanged in mass.
Explanation:
Robert Millikan, along with Harvey Fletcher, performed the famous oil drop experiment in 1909. By observing the motion of tiny charged oil droplets in an electric field, Millikan accurately determined the elementary charge of a single electron to be approximately 1.592 × 10^-19 coulombs (later refined to 1.602 × 10^-19 C).
Explanation:
Lavoisier is known for the law of conservation of mass, naming oxygen/hydrogen, and establishing chemistry as a quantitative science. Dalton proposed atomic theory; Mendeleev periodic table.
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