261. 15th group is called ……. group:
(a) Carbon                                            (b) Halogen
(c) Nitrogen                                          (d) Oxygen
Answer: (c)

262. Halogens belong to ……. group.
(a) 15th                                                  (b) 16th
(c) 17th                                                   (d) 18th
Answer: (c)

263. Compound that does not form a clear solution with cold water is 
Answer: Benzoic Acid 

264. The lightest noble gas is
Answer: Helium 

265. The light emitted during chemical reaction is called
Answer: chemiluminescence 

266. Amber colour is imparted to glass by adding 
Answer: carbon

267. Simpson and Harrison are associated with the invention of
Answer: Chloroform 

268. Epsom salt is
Answer: hydrated magnesium sulphate 

269. Penicillin was invented by Fleming in the year 
Answer:1929 

270. The salt is known as ‘Pearl ash’ is- 
Answer: Potassium carbonate 

271. The National Chemical Laboratory is situated in 
– Pune 

272. PVC plastics are obtained from vinyl chloride by the process of 
– polymerization  

273. Milk is an example of
– emulsion 

274. The boiling point of water, on the kelvin scale of temperature, is 
– 373 

275. The substance that causes the worst air pollution is
– carbon monoxide 

276. Dolomite is an ore of 
-Mg

277. The element used in photocopying machines is 
– Selenium 

278. In breeder reactors, uranium-238 is converted into 
– Plutonium-239 

279. The process of elimination of water from any system is called. 
– dehydration 
280. Chemotherapy deals with

– The study and uses of chemicals in the cure of diseases. 

281. The point at which the solid, liquid and gaseous forms of a substance co-exist is called its 
– triple point 

282. The IC chips used in computers are made of 
– Silicon 

283. For rural electrification and domestic cooking, most appropriate and economical would be 
– biogas 

284. The full form of D.D.T.:
Dichlorodiphenyltrichloroethane

285. The acid contained palm oil:
Palmitic acid 

286. Vinegar contains:
(a) Acetic acid (b) Lactic acid
(c) Malic acid (d) Citric acid
Answer: (a)

287. The acid contained in gastric juice:
(a) Prussic acid (b) Ascorbic acid
(c) Hydrochloric acid (d) Tartaric acid
Answer: (c)

288. What is known as the king of chemicals?
(a) Hydrochloric acid (b) Sulphuric acid
(c) Nitric acid (d) Acetic acid
Answer: (b)

289. The acid used for quick solidification of rubber latex:
(a) Lactic acid (b) Acetic acid
(c) Formic acid (d) Sulphuric acid
Answer: (c)

290. The acid contained in Grapes:
(a) Tartaric acid (b) Lactic acid
(c) Citric acid (d) Urine-Uric acid
Answer: (a)