Science Class 6th

281. ______ is used in fire extinguishers.

A. Hydrogen

B. Oxygen

C. Nitrogen

D. Carbon dioxide

282. _______ is used in soft drinks, washing soda, baking and photosynthesis.

A. Hydrogen

B. Oxygen

C. Carbon dioxide

D. None

283. Human beings inhale oxygen and exhale ___________

A. Carbon dioxide

B. Nitrogen

C. Hydrogen

D. Carbon

284. Rare gases are also called?

A. Inert

B. Noble

C. Both ‘a’ and ‘b’

D. None

285. Inert gases are chemically?

A. Active

B. Inactive

C. Sometimes active

D. None

286. Noble gases are?

A. Colorless

B. Ordorless

C. Both ‘a’ and ‘b’

D. None

287. Among Nobel gases,___________ is present in maximum amount.

A. Argon

B. Xenon

C. Krypton

288. Argon is present ______% by volume in air..

A. 0.8

B. 0.7

C. 0.5

D 0.9

289. _________ is filled in electric bulbs.

A. Argon

B. Xenon

C. Hydrogen

D. Krypton

290. Deep sea divers use mixture of _________.

A. Helium

B. Oxygen

C. Both ‘a’ and ‘b’

D. Argon

 

291. _______ signs are used in advertising board.

A. Neon

B. Argon

C. Hydrogen

D. Oxygen

292. ________ is filled in weather balloon.

A. Hydrogen

B. Oxygen

C. Helium

D. Argon

293. The droplets of water around cold glass of water are called?

A. Droplets

B. Ice

C. Water vapours

D. None

294. Oxygen is not necessary for?

A. Combustion

B. Rusting

C. Respiration

D. Photosynthesis

295. Carbon dioxide is used in?

A. Soft drinks

B. Fire extinguishers

C. Photosynthesis

D. All of these

296. Volume of oxygen in air is?

A. 22%

B. 21%

C. 25%

D. None

297. Inert gases are not used in?

A. Electric bulb

B. Sign boards

C. Photosynthesis

D. Weather balloons

298. Which gas is necessary for burning process?

A. Oxygen

B. Nitrogen

C. Carbon dioxide

D. Argon

299. A solution is ______ mixture of two or more substances.

A. Homogeneous

B. Heterogeneous

C. None of these

300. Solution can exist in ________ states of matter.

A. 3

B. 1

C. 4

D. 2