A solution turns red litmus blue. Its pH is likely:
A. 2
B. 5
C. 9
D. 7
Answer: Option C
Solution (By JKSSB Mock Tests)
A solution turning red litmus blue is basic, so pH > 7. Among options, pH 9 is basic. pH 2 and 5 are acidic (blue litmus turns red). pH 7 is neutral. Litmus is a natural indicator extracted from lichens. Red litmus in base remains blue, blue litmus in acid turns red. Practical: Phenolphthalein gives pink in basic solution (pH > 8.3).
Explanation:
Alkenes contain at least one carbon-carbon double bond. The simplest alkene is ethene (C₂H₄). Methane is an alkane; ethane is an alkane; propyne is an alkyne. General formula for alkenes: CₙH₂ₙ.
Explanation:
Zinc loses electrons: Zn → Zn²⁺ + 2e⁻, thus it is oxidized (increase in oxidation state from 0 to +2). Copper ions gain electrons: Cu²⁺ + 2e⁻ → Cu, thus copper is reduced. Zn acts as the reducing agent, CuSO₄ as the oxidizing agent. This is a single displacement redox reaction. Zn is more reactive than Cu.
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