191. Butane is used in-
cigarette lights.

192. A mixture of oxygen and acetylene gases are used for-
 gas welding.

193. Methane is the main component of-
 biogas.

194. The smell of cooking gas is due to the Ethyl Mercaptan which helps to-
 detect gas leakage.

195. Alnico is an alloy of aluminium used for-
 making magnets.

196. Duralumin is an alloy of aluminium (94%), copper (4%) and Magnesium (1%) used for –
constructing air crafts.

197. Invar is a nickel-iron alloy used for-
 making clocks.

198. Aspirin or Acetylsalicylic acid is used as a –
pain killer and it has anti-inflammatory properties.

199. Tri Nitro Toluene (TNT) is used as an-
 explosive.

200. The most commonly used Synthetic rubber is-
 styrene Buta-diene rubber (SBR).

201. The electrodes of dry cell are made up of-
 Graphite.

202. Acid rain is caused by the pollution of the environment due to-
 nitrogen oxide and sulphur dioxide.

203. The most chemically active element is-
 Fluorine.

204. Chlorofluro carbon (CFCs) used in refrigerators causes-
ozone hole formation.

205. Sodium/Potassium salt of stearic acid, palmitic acid and oleic acid is-
 soap.

206. Aqua Regia is a mixture of concentrated nitric acid and hydrochloric acid which can dissolve-
 gold and platinum.

207. Coins are made of coinage alloy which consists of-
 copper and nickel.

208. Coloured glasses for goggles contain-
 ferrous oxide.

209. Coating of iron with zinc to prevent rusting is called-
 galvanisation.

210. Lead is used in petrol as an –
antiknocking agent. 

211. Natural gas predominantly contain —
methane.

212. Liquified Petroleum Gas mainly consists of-
 liquified butane and isobutane.

213. Ethylene is used for the artificial ripening of-
 green fruit.

214. Gelatine is used in the manufacture of ice cream too –
 prevent crystal growth.

215. Vulcanisation is the process of adding sulphur to rubber to make it-
 strong and bounceable

216. Non-stick kitchenware is coated with-
 Teflon (Poly tetra Fluro Ethylene) and potassium hydrogen tartrate.

217. Stainless Steel is an alloy of –
iron (73%), Carbon(1%), Chromium (18%) and Nickel (8%)

218. Solder is an Alloy of-
lead (50%) and tin (50%)

219. Bronze is an alloy –
of copper and tin.

220. Brass is an alloy of-
 copper (60-80%) and Zinc (40-20%)

221. Mercury and gallium are metals which are liquids at-
 room temperature.

222. The hardest metal is –
Tungsten.

223. Wrought iron is the purest type of iron that contains-
least amount of carbon. 
          
224. Silver, gold and platinum are known as –
noble metals.

225. Metals which has the highest density is-
Osmium