Osb India Class 10 Weekly test Question paper From chemical reaction and equation and acid base and salt

 

1. In the electrolysis of water, a) Name the gas collected at anode and cathode b) Why is the volume of gas collected at one electrode double than the other? c) What would happen if dil H₂SO₄ is not added to water? ( 3 Marks)
2. While writing chemical equations for such reactions, where are these conditions usually mentioned?
A. above the arrow B. along with products C. below the plus signs D. before the reactants ( 1 Marks)
3. Chemical equations are balanced to reflect that ___________________.
A. matter can change its state during chemical reactions B. matter cannot be created or destroyed during chemical reactions
C. heat is an important input in chemical reactions D. all chemical reactions are always reversible (1 Marks)
4. Which of the following is TRUE about a combination reaction? A. The number of reactants is always greater than the number of products. B. The number of products is always greater than the number of reactants. C. The number of products is always equal to the number of reactants. D. (Any of the above can be true for different reactions.) (1 Marks)
5. Which of the following are properties of acids? P. They are bitter in taste. Q. They react with metals to produce hydrogen gas.
R. They are easily soluble in water. A. only P   B. only P and R    C. only Q and R     D. all - P, Q and R (1 Marks)
6. . w SnO2 + x H2 ---------> y Sn + z H2O For which of the following values of w, x, y and z will the equation above be balanced?
A. w=1, x=1, y=1, z=1      B. w=1, x=2, y=2, z=1      C. w=1, x=2, y=1, z=2        D. w=1, x=1, y=1, z=2
7. A solution of an acid with pH 5.1 is given. Which of the following can be done to increase its pH?
i. add distilled water to it ii. add a solution of a different acid with pH 5.8 iii. add few drops of a base with an unknown pH
A. only I B. only iii C. only i and ii D. any of i, ii and iii
8. Payal has to arrange the following in DECREASING order of hydroxide ion concentration. wine (pH 4.0), milk of magnesia (pH 10.5), blood (pH 7.4) Which of the following arrangements is correct?
A. wine -> milk of magnesia -> blood B. blood -> milk of magnesia -> wine C. milk of magnesia -> blood -> wine D. wine -> blood -> milk of magnesia
9. A piece of zinc (Zn) - a reactive metal - was dropped into a test tube containing a substance. A zinc salt was formed and hydrogen gas was liberated. This is shown in the equation below. Zn + _____ ----------> zinc salt + H2 gas
Which of the following can be the substance that zinc was dropped into? P) water Q) hydrochloric acid R) a solution of a zinc salt
A. only P B. only Q C. only R D. either P or R
10. Two statements are given - one labelled Assertion (A) and the other labelled Reason (R).
Assertion: Sodium carbonate is commonly used as an ingredient in antacid tablets.
Reason: Sodium carbonate is a basic salt.
Which of the following is correct? A. Both A and R are true, and R is the correct explanation of A. B. Both A and R are true, but R is not the correct explanation of A. C. A is true, but R is false. D. A is false, but R is true
 Battery acid < 1.0, Stomach acid 2.0, Lemon juice 2.4, Cola 2.5, Apple juice 3.5, Black Coffee 5.0, Black tea 5.5, Acid rain 5.6, Milk 6.5, Distilled water 7.0, Human saliva 7.5, Sea water 8.0, Soap 9.0 - 10.0, Milk of magnesia 10.5, Ammonia 11.5, Bleach 12.5
11. Which of these is a neutralisation reaction? A. mixing sea water and bleach B. mixing lemon juice and soap C. mixing milk and black tea D. mixing cola and distilled water
12. Which of these is a valid conclusion that can be drawn from the table?
A. Many common food items are quite acidic in nature. B. Our stomach contains a liquid which is a weak acid. C. Sea water is neither acidic nor basic - it is neutral. D. Acid rain, in spite of its name, is basic in nature.
13. Amit has black coffee with milk. Which of the following is most likely to be true about the pH of the mixture?
A. It will be less than that of black coffee. B. It will be more than that of distilled water. C. It will be more than that of acid rain. D. It will be less than that of apple juice
14. Which of the following would be the best for a person suffering from acidity? A. cola B. milk C. black tea D. milk of magnesia
15. How will you protect yourself from the heat generated while diluting a concentrated acid? A. By adding acid to water with constant stirring. B. By adding water to acid with constant stirring. C. By adding water to acid followed by base. D. By adding base to acid with constant stirring.
16. Why is it important to balance a skeletal chemical equation? A. To verify law of conservation of energy. B. To verify the lawof constant proportion. C. To verify the law of conservation of mass. D. To verify the l0aw of conservation of momentum.17. Vinay observed that the stain of curry on a white shirt becomes reddish-brown when soap is scrubbed on it, but it turns yellow again when the shirt is washed with plenty of water. What might be the reason for his observation?i. Soap is acidic in nature ii. Soap is basic in nature iii. Turmeric is a natural indicator which gives reddish tinge in bases iv. Turmeric is a natural indicator which gives reddish tinge in acids A. i and ii B. ii and iii C. i and iv D. ii and iv 18. What is meant by a chemical reaction? (1 Marks)