5. What happens when carbon dioxide passes through lime water?
6. What are the applications of neutralization reaction in everyday life?
7. Write about clinical thermometer.
8. What are the various steps for processing fibres into wool?
Answers
5.
Carbon dioxide reacts with limewater (a solution of calcium hydroxide, Ca(OH) 2), to form a white precipitate (appears milky) of calcium carbonate, CaCO 3. Adding more carbon dioxide results in the precipitate dissolving to form a colourless solution of calcium hydrogencarbonate.
6.Sodium hydroxide: used in the production of soaps, paper, and synthetic fibres. Magnesium hydroxide: used as an antacid to neutralise the acid in the stomach. Ammonium hydroxide: manufacturing of fertilisers. Calcium hydroxide: used for manufacturing bleaching powder.
7.A clinical thermometer is a thermometer used to measure human body temperature. Most made in the 20th century are mercury-in-glass thermometers. They are accurate and sensitive, having a narrow place where the mercury level rises very fast. A kink in the tube stops the mercury level from falling on its own.
8. The steps involved for processing fibres into wool are shearing, scouring from sheep, sorting, dyeing, straightening, rolling and combing.