261.  The branch of chemistry in which we study hydrocarbon and their derivatives is called
(A) Organic chemistry
(B) Inorganic chemistry
(C) Industrial chemistry
(D) Biochemistry

262. The metal present in combined state is called
(A) solid
(B) compound
(C) mineral
(D) None of these

263. Which of the following is homogeneous mixture?
(A) Smoke
(B) Fog
(C) Smog
(D) Air

264. The major component of troposphere is
(A) Argon
(B) Carbon
(C) Hydrogen
(D) Nitrogen

265. Ozone depletion causes
(A) Blood Cancer
(B) Skin Cancer
(C) Malaria
(D) T.B

266. The pH of the acid rains is less than
(A) 5.6
(B) 5.1
(C) 4.6
(D) 4.1

267. Ozone is a ____________ gas.
(A) Reddish
(B) Greenish
(C) Bluish
(D) Yellowish

268. In water, ratio of oxygen and hydrogen by mass is
(A) 1:3
(B) 2:1
(C) 1:2
(D) 8:1

269. Wheat, rice, and honey are the sources of
(A) Lipids
(B) Proteins
(C) Vitamin
(D) Carbohydrates

270. Polymers of amino acids are called
(A) Vitamin
(B) Proteins
(C) Lipids
(D) Maltose