After extended stirring of a spatula sized portion of a solid drug in 100 mL of water, the drug appeared to be insoluble. Yet when the liquid was separated from the solid and heated, solid residue was observed forming as the liquid evaporated. This evidence suggests that the liquid portion of the mixture formed after stirring the drug with water was

a saturated solution

Explanation:

A saturated solution is a solution that already contains just as much solute as it can normally hold at a given temperature.

When more solute is added to a saturated solution, the added solute does not dissolve.

The fact that when the liquid was separated and evaporated, some solid crystals were recovered means that the liquid has already dissolved the amount of solute that it can normally hold at that temperature. That is, the liquid is already a saturated solution hence more solute does not dissolve.

state the principle of separating two immiscible liquids by separating funnel. describe an activity with diagram to separate a mixture of water and kerosene oil. answer: immiscible layers separate out in layers depending on their densities in separating funne

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.