CBSE ADDA

MCQ Sample Question Paper  X  Based On Practical skill 1. When we start heating a mixture of sulphur powder and iron fillings, we would observe  that (a) Surphur starts melting.                   (b) Iron filings start melting. (c) Mixture becomes red hot.  (d) mixture evaporates Ans (a) Sulphur has a lower melting point than iron. 2 A student added 2 drops of iodine solution into 4 ml of starch solution in test tube  A, another student added 2 ml of starch solution into 4 ml of iodine solution in test tube B. They would then observe (a) a change of colour to blue black in test tube A but not in test tube B. (b) a change of colour to blue black in test tube B but not in test tube A. (c) a change of colour to blue black in both test tubes A and B (d) no change of colour in any test tube. Ans

Chemistry X –Ch apter :Metal and Non Metal SA-I Guess Question CBSE HOTS QUESTIONS (SOLVED :JSUNIL TUTORIAL) Q.1 What are amphoteric oxides? Why is it that non metals do not displace hydrogen from dilute acid? Ans. The oxides which are acidic as well as basic in nature are called amphoteric oxides. ZnO and Al 2 O 3  are amphoteric oxides.            Al 2 O 3  + 6HCl ® 2AlCl 3  + 3H 2 O            Al 2 O 3  + 2NaOH ® 2NaAlO 2  + H 2 O Non metals cannot lose electrons so that H +  ions become hydrogen gas. Q.2. What is anodizing? What is its use? Ans. The process of forming thick oxide layer of aluminium oxide that makes it resistant to further corrosion. Q.3. What is Aqua regia? What is its use? Ans. It is a mixture of concentrated HCl and concentrated HNO 3  in the ratio 3:1. It can dissolve gold and platinum. It dissolve g