CBSE Class-10 Exam 2016 : Foreign Scheme
Question Paper, Science
CBSE Class-10 Exam 2016 : Science
Time allowed : 3 hours
Maximum Marks : 90
SECTION – A
1. Which element exhibits the property of catenation to maximum extent and why ?
2. Name the method by which hydra reproduces. Is this method sexual or asexual ?
3. We often use the word environment. What does it mean ?
4. AB and CD, two spherical mirrors, form parts of a hollow spherical ball with its centre at O as shown in the diagram. If arc AB = 1/2 arc CD, what is the ratio of their focal lengths ? State which of the two mirrors will always form virtual image of an object
placed in front of it and why.
5. What is sustainable development ? State its two main objectives.
6.List four causes of damage to forests.
7. Write the name and molecular formula of an organic compound having its name suffixed with ‘ol’ and having two carbon atoms in its molecule. Write balanced chemical equation to indicate what happens when this compound is heated with excess
conc. H2SO4 and the name of main product formed. Also state the role of conc. H2SO4 in the reaction.
8. An organic compound ‘P’ is a constituent of wine. ‘P’ on reacting with acidified K2Cr2O7 forms another compound ‘Q’. When a piece of sodium is added to ‘Q’ a gas ‘R’ evolves which burns with a pop sound. Identify P, Q and R and write the chemical
equations of the reactions involved.
9. State the main aim of classifying elements. Which is the more fundamental property of elements that is used in the development of Modern Periodic Table ? Name and state the law based on this fundamental property. On which side of the periodic table one can find metals, non-metals and metalloids ?
10. An element ‘X’ (Atomic number = 20) burns in the presence of oxygen to form a basic oxide.
(a) Identify the element and write its electronic configuration.
(b) State its group number and period number in the Modern Periodic Table.
(c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.
11. What is Pollination ? List its two types and write a distinguishing feature between the two.
12. What happens when
(a) Planaria gets cut into two pieces ?
(b) A mature spirogyra filament attains considerable length ?
(c) On maturation sporangia burst ?
13. What is sexual reproduction ? List its four significances.