Which of the following is a method to remove permanent hardness of water?
A. Filtration
B. Boiling
C. Cooling
D. Adding washing soda
Answer: Option D
Solution (By JKSSB Mock Tests)
Permanent hardness (due to CaSO₄ etc.) can be removed by adding Na₂CO₃, which precipitates CaCO₃. Boiling only removes temporary hardness. Ion exchange and calgon also work.
Explanation:
Cathode rays consist of electrons, which are fundamental particles. Therefore, their nature (charge to mass ratio) is independent of the gas used in the cathode ray tube or the material of the cathode. All other statements are correct properties of cathode rays, demonstrating their fundamental particle nature.
Explanation:
Methane (CH₄) is released from enteric fermentation in livestock (cattle) and from anaerobic decomposition in flooded rice paddies. It has a high global warming potential (25× CO₂ over 100 years). CO₂ mainly from fossil fuels. N₂O from fertilizers. CFCs from refrigerants. Agriculture contributes significantly to anthropogenic GHG emissions. Reducing methane can have rapid climate benefits.
Explanation:
In a galvanic (voltaic) cell, chemical energy converts to electrical energy. Oxidation occurs at the anode, which is the negative electrode (electrons leave from it). Reduction occurs at the cathode, which is positive. This is opposite to electrolytic cell where anode is positive. Daniell cell: Zn anode (-), Cu cathode (+).
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