Q1. Which of the following takes place when water transforms from liquid to gaseous phase?
(a) Distance between the particles changes
(b) The color of the particles changes
(c) Size of the particles change
(d) Structure of the particles change
Q2. Anita prepared a fresh solution of sodium hydroxide in a test tube.
She dropped a small piece of aluminium of foil into it and then brought a burning matchstick near the mouth of the test tube. she hears a pop sound. The pop sound indicates the presence of
(a) Hydrogen gas
(b) Aluminium gas
(c) Water gas
(d) Oxygen gas
Q3. Read the following example from daily life and select the appropriate option.
I. When food gets spoiled, then it produces a foul smell.
II. A slice of apple acquires brown color when kept out for some time.
III. When an ant bites, then calamine is used to ease the irritation on skin.
(a) Only II is a physical change
(b) both I and II are physical change
(c) All are chemical changes
(d) Both I and II represent chemical changes
Q4. The melting points (in℃) of Sulphur(S), aluminium(Al) and iron (Fe) are 113, 666 and 1535, respectively. Which one of the following is correct?
(a) Only Fe is solid at 200℃.
(b) Both Al and Fe are solids at 200℃.
(c) Fe, S and Al are solids at 200℃.
(d) Only S is solid at 200℃.
Q5. Read the given statement and select the correct option.
I. Husk is separated from heavier seeds of grain by winnowing.
II. Difference in the size of particles in a mixture is utilized to separate them by the process of sieving and filtration.
(a) Statement II is true and Statement I is false
(b) Both statements I and II are false
(c) Both statements I and II are true
(d) Statement I is true and Statement II is false
Q6. A student burns a magnesium ribbon in air dissolves the ash of the ribbon left after burning in distilled water. On pouring one drop each of this solution, first in blue litmus and then in red litmus solution, he would observe that
(a) Blue litmus turns red, whereas the red litmus remains red
(b) Blue litmus turns red, whereas the red litmus turns blue
(c) Blue litmus turns colorless whereas the red litmus remains red
(d) Blue litmus remains blue, whereas the red litmus turns blue
Q7. “Copper cannot displace zinc from its salt solution. “Give the reason.”
The following reasons are given by Class VIII students.
I. Copper is more reactive than zinc.
II. Copper is less reactive than zinc.
III. Zinc is one of the noble metals.
IV. Zinc appears below copper in reactivity series.
Select the correct reason(s) from the reasons given by class VIII students.
(a) Only I
(b) II and IV
(c) Only II
(d) I and IV
Q8. The melting point of sulphur is 113℃ and its boiling point is 445℃. which one of the following statements is incorrect?
(a) Sulphur is solid at 90℃
(b) Sulphur is liquid at 400℃
(c) Sulphur is liquid at 450℃
(d) Sulphur is solid at 20℃
Q9. When candle burns
I. its size decreases.
II. there is melting of wax.
III. flame and soot can be seen.
IV. Melted wax also solids.
From the above observation, which one of the following is correct?
(a) Only I is a physical change and other are chemical changes
(b) Only II is a chemical change and others are physical changes
(c) I and II are physical changes and III and IV are chemical changes
(d) I, II and III are physical changes
Q10. Sodium and potassium are stored in Kerosene. Give reason.
The following reasons are given by class VIII students.
I. Both are highly reactive and react with carbon dioxide in the atmosphere.
II. Both are highly toxic and gives off toxic fumes.
III. Both are highly reactive and react with oxygen in atmosphere.
IV. Kerosene helps cut off the reaction of the metals with oxygen in the air.
Select the most appropriate reason(s) given by class VIII students.
(a) Only I
(b) II and IV
(c) Only II
(d) III and II
S1. Ans. (a)
S2. Ans. (a)
S3. Ans. (c)
S4. Ans. (b)
S5. Ans. (c)
S6. Ans. (d)
S7. Ans. (c)
S8. Ans. (c)
S9. Ans. (b)