Who performed the oil drop experiment to determine the charge of an electron?
A. Robert Millikan
B. Ernest Rutherford
C. James Chadwick
D. Henry Moseley
Answer: Option A
Solution (By JKSSB Mock Tests)
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:
2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O. Carbon dioxide is released, which turns limewater milky. This is a test for bicarbonates. Oxygen is not produced; hydrogen would need a reducing agent.
Explanation:
Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. Benzene (C6H6) has a ring structure with alternating double bonds (delocalized pi electrons), making it highly unsaturated. Cyclohexane, propane, and methane contain only single bonds and are saturated hydrocarbons.
Explanation:
Red litmus turning blue indicates a basic solution, pH > 7. pH 11 is strongly basic. pH 3 and 6 are acidic (blue litmus turns red). pH 7 is neutral (litmus remains purple). Litmus is a common natural indicator.
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