One end of a match is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface. The coated end of a match, known as the match "head," contains either phosphorus or phosphorus sesquisulfide as the active ingredient and gelatin as a binder.

Correct Option: A

One end of a match is coated with a material that can be ignited by frictional heat generated by striking the match against a suitable surface. The coated end of a match, known as the match "head," contains either phosphorus or phosphorus sesquisulfide as the active ingredient and gelatin as a binder.

Titanium is the hardest natural metal in the world. It is very strong, three times the strength of steel and much stronger than gold, silver and platinum and yet is very light weight. Tungsten carbide is the hardest metal alloy on Earth and is scratch proof under normal wear. Tungsten carbide is two times as hard as steel and four times as hard as titanium.

Correct Option: D

Titanium is the hardest natural metal in the world. It is very strong, three times the strength of steel and much stronger than gold, silver and platinum and yet is very light weight. Tungsten carbide is the hardest metal alloy on Earth and is scratch proof under normal wear. Tungsten carbide is two times as hard as steel and four times as hard as titanium.

Silver bromide, a soft, pale-yellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials.

Correct Option: B

Silver bromide, a soft, pale-yellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials.

Aqua regia or nitro-hydrochloric acid is a highly corrosive mixture of acids, a fuming yellow or red solution. It was named so because it can dissolve the so-called royal or noble metals, gold and platinum.

Correct Option: C

Aqua regia or nitro-hydrochloric acid is a highly corrosive mixture of acids, a fuming yellow or red solution. It was named so because it can dissolve the so-called royal or noble metals, gold and platinum.

Yeasts are eukaryotic microorganisms classified in the kingdom Fungi. By fermentation, the yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols – for thousands of years the carbon dioxide has been used in baking and the alcohol in alcoholic beverages.

Correct Option: C

Yeasts are eukaryotic microorganisms classified in the kingdom Fungi. By fermentation, the yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols – for thousands of years the carbon dioxide has been used in baking and the alcohol in alcoholic beverages.