Q1. Why H2O is liquid and H2S is a gas?
(a) oxygen forms stronger hydrogen bond than sulphur.
(b) oxygen is less electronegative than sulphur.
(c) atomic radius of oxygen is less than that of sulphur.
(d) atomic radius of oxygen is greater than that of sulphur.
Q2. Which of the following is the nuclear fuel in the sun?
(d) alpha particles
Q3. ‘Acid rain’ is caused due to air-pollution by-
(a) carbon dioxide
(b) carbon monoxide
(d) nitrous oxide and sulphur dioxide
Q4. Which device is used for the measurement of radioactivity?
(a) Mass spectrometer
(c) Nuclear reactor
(d) G.M. counter
Q5. To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is—
Q6. The metal constituent of chlorophyll is—
Q7. When soggy biscuits are kept inside the fridge for some time they become crisp because—
(a) cooling releases extra moisture
(b) humidity inside the fridge is low and extra moisture is absorbed
(c) humidity inside the fridge is high and extra moisture is absorbed
(d) pressure inside the fridge is high and helps in releasing extra moisture
Q8. Which one of the following mixtures is homogeneous?
(a) Starch and sugar
(b) Methanol and water
(c) Graphite and charcoal
(d) Calcium carbonate and calcium bicarbonate
Q9. Which of the following statements is correct for solid state?
(1) The constituent particles are closely packed
(2) The attracting forces are very strong
(3) The movement of constituent particle is restricted
(4) They do have fixed shape
(a) (1), (2) and (3) are correct
(b) (2) and (3) are correct
(c) (1) and (2) are correct
(d) All of these
Q10. Rate of reaction of organic compounds is slow due to-
(a) ionic bonding in them
(b) amphoteric nature
(c) coordinate covalent bonding
(d) covalent bonding
Q11. Match the following with correct response.
(1) Dry ice
(4) Liquefied gas
(A) Reduce evaporation
(B) Increasing pressure reducing temperature
(C) Increases evaporation
(D) Solid carbon-dioxide
(a) 1-C, 2-B, 3-D, 4-A
(b) 1-D, 2-A, 3-C, 4-B
(c) 1-A, 2-C, 3-B, 4-D
(d) 1-B, 2-D, 3-A, 4-C
Q12. Silicon is used in which of the following?
(b) solar energy devices
(d) All of these
Q13. Uric acid is present in which of the following?
(a) Soda water
(b) Rancid butter
(c) Sour milk
(d) Urine of mammals
Q14. Consider the following statements:
1. Diamond is hard and graphite is soft.
2. Diamond is soft and graphite is hard.
3. Diamond is a bad conductor but graphite is a good conductor.
4. Diamond is a good conductor but graphite is a bad conductor.
Which of the statements given above is/are correct ?
(a) 1 and 3
(b) 1 only
(c) 2 and 3
(d) 1 and 4
Q15. It is more comfortable to wear white clothes in summer because
(a) they reflect heat falling on them.
(b) they radiate heat transferred from the body.
(c) they absorb perspiration.
(d) they are soothing to the eye.