SELECT * FROM question_mgmt as q WHERE id=667 AND status=1 SELECT id,question_no,question,chapter FROM question_mgmt as q WHERE courseId=3 AND subId=9 AND chapterId=60 and ex_no='1' AND status=1 ORDER BY CAST(question_no AS UNSIGNED) CBSE Free NCERT Solution of 12th chemistry Surface Chemistry why is it essential to wash the precipitate with w

Question:

Why is it essential to wash the precipitate with water before estimating it quantitatively?

Answer:

The precipitate (product) formed out from any chemical reaction always contains some traces of unwanted materials (unreacted reactants or catalyst and certain impurities). These unwanted materials adsorbed onto the surface of the required product and settle down at the bottom of the container. For quantitative estimation of the product, these unwanted materials has to be removed. For removal of unwanted materials, different methods are used, one of them is washing with water. Because most of the impurities are water soluble, so they can be easily removed from the product. Water easily makes hydrogen bond with most of the elements (polar). After washing with water, the unwanted materials gets dissolved in water and removed out from the final product.


SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='3' AND subId='9' AND ex_no!=0 AND status=1 and id!=667 ORDER BY views desc, last_viewed_on desc limit 0,10
SELECT ex_no,question,question_no,id,chapter FROM question_mgmt as q WHERE courseId='3' AND subId='9' AND ex_no!=0 AND status=1 and id!=667 ORDER BY last_viewed_on desc limit 0,10

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  • Answered by Ekta Mehta
  • 4 months ago

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