121. The most flexible metal is?
Answer: Silver
122. The reaction of Iron (III) Oxide with _______ is used for joining railway tracks or broken machine parts.
Answer: Aluminum
123. The oxide of _______ cannot be reduced by carbon.
Answer: Al
124. Coating steel and iron with a thin layer of zinc to prevent rusting is called?
Answer: Galvanization
125. Bronze is an alloy of copper and _______.
Answer: Tin
126. The decomposition of vegetable matter in compost is an example of a _______ reaction.
Answer: Exothermic
127. Plaster of Paris is called _______.
Answer: CaSO₄ ½ H₂O
128. An alloy of lead and tin is called _______.
Answer: Solder
129. Zinc and lead are more reactive than _______.
Answer: Copper
130. When fats and oils are ________, they become rancid and their smell and taste change.
Answer: Oxidized
131. When magnesium ribbon is burned in a bright white flame, it turns into a white powder. That powder is
Answer: Magnesium Oxide
132. Name the compound that is used to remove the permanent hardness of water.
Answer: Sodium Carbonate
133. Calcium oxide reacts vigorously with water to produce _______.
Answer: Slaked Lime
134. After two to three days of whitewashing, a compound is formed that gives a shiny finish to the walls.
Answer: Calcium Carbonate
135. The chemical formula of marble is
Answer: CaCO₃
136. Our stomach produces _______ which helps in the digestion of food.
Answer: Hydrochloric Acid
137. Tooth enamel, the hardest substance in our body, is made of
Answer: Calcium Phosphate
138. The chlor-alkali process is used to produce _______.
Answer: NaOH
139. Bleaching powder is produced by the action of chlorine on _______.
Answer: Dry Slaked Lime
140. Sodium hydrogen carbonate (NaHCO₃) is
Answer: Baking Soda