261. The color of the Taj Mahal in Agra has changed due to _______.
Answer: Acid rain
262. Antacids are used to remove _______.
Answer: Acidity
263. The chemical compound present in toothpaste is
Answer: Alkaline – Ca₃(PO₄)₂
264. The pH of orange juice is
Answer: 3.00 – 3.75
265. The acid that helps in digestion is
Answer: Hydrochloric acid
266. Crystallization water does not occur in _______.
Answer: Baking soda (Sodium bicarbonate)
267. Plaster of Paris is
Answer: CaSO₄ · ½H₂O
268. Acetic acid reacts with NaOH to form a salt, which has a pH of
Answer: Greater than 7
269. When a metal is brought into contact with acid or alkali, a gas is released. The gas is
Answer: Hydrogen
270. _______ has high tensile strength.
Answer: Au
271. The method used to prevent the corrosion of aluminum is
Answer: Passivation
272. Metal ‘A’ reacts with dilute HNO₃ to release hydrogen. A is
Answer: Mg
273. The metal that is extremely reactive is
Answer: Al
274. The compound among the following that is polar is
Answer: Alcohol
275. The extraction of metals can be easily done from _______.
Answer: Ore
276. The metal that is found in its native form is
Answer: Pt
277. When brass is kept in contact with air for a long time, its color turns green due to _______ formation.
Answer: Formation of Cu(OH)₂
278. The alloy used for soldering is
Answer: Lead and Antimony
279. The liquid non-metal among the following is
Answer: Br
280. Brass is an alloy of _______.
Answer: Cu and Zn