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A certain salt (X) gives the following tests : (a) Its aqueous solution is alkaline to litmus. (b) On strong heating, it swells up to give a glassy material (Y). (c) When conc. H_(2) SO_(4) is added to a hot concentrated solution of (X), white crystal ofa weak acid (Z) separates out. Identify (X), (Y) and (Z) and write down the chemical equations for reaction at steps a, b and c.

Answer» <html><body><p></p>Solution :(i) <a href="https://interviewquestions.tuteehub.com/tag/since-644476" style="font-weight:bold;" target="_blank" title="Click to know more about SINCE">SINCE</a>, the alkaline solution of the given salt [X] is alkaline to litmus, it <a href="https://interviewquestions.tuteehub.com/tag/must-2185568" style="font-weight:bold;" target="_blank" title="Click to know more about MUST">MUST</a> be a salt of strong base and weak acid. <br/> (ii) The salt [X] on heating <a href="https://interviewquestions.tuteehub.com/tag/swells-1236482" style="font-weight:bold;" target="_blank" title="Click to know more about SWELLS">SWELLS</a> up to a <a href="https://interviewquestions.tuteehub.com/tag/glassy-2674980" style="font-weight:bold;" target="_blank" title="Click to know more about GLASSY">GLASSY</a> material (Y). Therefore, [X] should be borax and [Y] a mixture of sodium metaborate and boric anhydride. <br/> (iii) When conc. H2SO4 is added to a hot solution of borax [A], white crystals of orthoboric acid [Z] <a href="https://interviewquestions.tuteehub.com/tag/separate-1201161" style="font-weight:bold;" target="_blank" title="Click to know more about SEPARATE">SEPARATE</a> out. Hence, [X] = `Na_2 B_4 O_7 . 10 H_2 O , [Y] = NaBO_2 + B_2 O_3 and [Z] = H_3 BO_3`. <br/>The reaction can be expressed as follows : <br/><img src="https://doubtnut-static.s.llnwi.net/static/physics_images/NTN_HCS_ISC_CHE_XI_P2_C11_E09_050_S01.png" width="80%"/></body></html>


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