Statement 1 is correct: Hard water, rich in calcium and magnesium, can contribute to dietary intake of these minerals, but prolonged consumption may lead to kidney stones and urinary tract issues, particularly for susceptible individuals. Research indicates that high calcium levels can affect renal function. Statement 2 is correct: When hard water is used with soap, it forms soap scum, which reduces lather and makes washing less effective. Scum leaves residue on clothes, making them feel rough and unclean. This can also increase detergent usage. Statement 3 is correct: The minerals in hard water like calcium carbonate and magnesium salts, form scale in boilers and pipes, reducing thermal efficiency and leading to energy wastage and equipment failure. Statement 4 is correct: Continuous irrigation with hard water results in soil salinization, decreasing permeability and crop yield. Excess minerals like calcium and magnesium hinder plant nutrient absorption due to reduced soil’s permeability. Directions: The following two Items consist of statements. One labeled as the ‘Assertion (A)’ and the other as ‘Reason (R)’. You have to answer these items using the code given below: 334. Assertion (A): To dilute sulphuric acid, acid is added to water and not water to acid. Reason (R): Specific heat of water is quite large.
✓ Correct answer: a) Both A And R are true and R is the correct explanation of A
ExplanationAssertion (A) is true: This is done to ensure safety because diluting sulphuric acid is an exothermic process, meaning it releases heat.Adding water to concentrated sulphuric acid can cause a rapid release of heat, leading to a violent reaction and potential splattering of acid.By adding acid to water slowly while stirring, the heat generated is more easily dissipated.Reason (R) is true: Specific heat is the amount of heat energy required to raise the temperature of a substance.Water has a relatively high specific heat, meaning it can absorb and distribute a large amount of heat without a significant change in temperature.This property of water allows it to handle the heat generated during the dilution of sulphuric acid without causing a sudden increase in temperature.Thus Reason (R) correctly explains Assertion (A).UPSC GS Paper-I PYQs 606 335
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