The disinfectant used in municipal water supply that provides residual protection is:
A. Ozone
B. Chlorine
C. Boiling
D. UV radiation
Answer: Option B
Solution (By JKSSB Mock Tests)
Chlorine leaves a residual in water, continuing to protect against recontamination in distribution pipes. Ozone and UV kill instantly but do not provide residual disinfection. Boiling is not used for municipal supply.
Explanation:
Cathode is where reduction takes place (gain of electrons). In electrolytic cells, cathode is negative (connected to negative terminal of battery). Cations migrate to cathode and are reduced.
Explanation:
The reactivity of metals with water depends on their position in the reactivity series. Sodium and potassium are highly reactive alkali metals that react vigorously and exothermically with cold water to form hydroxides and hydrogen gas. Iron reacts only with steam, while copper and silver do not react with water.
Explanation:
Fossil fuels (coal, petroleum, natural gas) are formed from organic matter deposited in sedimentary layers, subjected to heat and pressure over geological timescales. They are non-renewable because their formation takes millions of years.
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