Chemical Elements and Their Properties

It contains up to 1.5% carbon. Increases the carbon content makes the iron harder, but more brittle thus it is used for cutting tools and masonry nails. Masonry nails are designed to be hammered into concrete blocks and if a worker miss hit a masonry nail, it tends to break into two bits because of its increased brittleness.

Iron supplements contain soluble iron(II) salts to replenish them in the human body in case of deficiency. Iron supplements usually contain about 50mg per tablet of iron(II). Potassium manganate(VII), Mr = 158.034, is a good primary standard, being available to a high degree of purity, having a large relative mass and being stable in the environment thus it is used to determine the percentage of iron in the tablets by titration.

It is a lattice structure where the layers can slide over each other easily to be drawn out into a wire. The atoms are all the same unlike in an alloy so it is easy to draw out into a wire thus it is the correct answer.

HCl dissociates into ions in water but remains as molecules in organic solvents. All properties are related to this only eg it conducts electricity in water but not in methylbenzene.

Sodium reacts with all liquids having -OH group as water , alcohols, phenols and carboxylic acids. 2- propanol is isopropyl alcohol,  so sodium forms Sodium isopropoxide and evolves hydrogen gas thus this option is used to dispose of Na metal.