CBSE ADDA

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

MODEL QUESTION PAPER(2012) Class: VII  Sub: Science Marks: 60 General Instructions: i. The question paper consists two sections, A and B. You are to attempt both the sections. ii. All questions are compulsory. iii. There is no overall choice. However, internal choice has been provided in all the three questions of five marks category. Only one option in such questions is to be attempted. iv. All questions of section A and all questions of Section B are to be attempted separately. v. Question numbers 1 to 3 in section A are one mark questions. There are to be answered in 1 word or in 1 sentence. vi. Question numbers 4 to 6 are two mark questions, to be answered in about 30 words each. vii. Question numbers 7 to 14 are three marks questions, to be answered in about 50 words each. viii. Question numbers 15 to 17 are five marks questions, to be answered in about 70 words each. ix. Question numbers 18 to 29 in section B are multiple choice que

Stars and The Solar System (Physics) Formative and Summative Assessments Oral Questions : CCE Pattern Class VII(8 th ) 1.  What is the vast space which includes everything around us called? Ans: Universe 2. Name the various objects that constitute the universe? Ans: All the stars, the sun, the planet and their moon, meteorites, comets. 3. What is the distance travelled by light in one year called? Ans: One light year=9460 billion kilometer 4. How much time sunlight takes to reach the earth? Ans: 8.3 sec. 5. What material the stars are made up of? Ans: Hydrogen gas 6. Name the celestial bodies you see in night sky? Ans: stars 7. Why celestial bodies appear to move from east to west in the sky? Ans: This is because the earth rotates from west to east. 8. Name the stars which appear stationary when sea from earth?