Answer:
He will decide which drink is to be served to whom, by the use of litmus paper.
Explanation:
The litmus paper is the most common indicator to determine the acidity or basicity of a solution. Blue litmus paper changes its color to red when a solution changes from basic to acidic while red litmus paper changes its color to blue when the opposite occurs (acid → basic).
First of all the litmus paper strip, pH indicator, is immersed in a solution and allowed to pass between 10 and 15 seconds while keeping the strip submerged. Afterwards it is removed, and then the strip compares the color. If the color is diffuse, there is a color scale where it is determined which solution has alkaline or acidic pH
Answer : Colloid
Explanation : Any colloid which consist of a solid evenly dispersed in a gas phase can be called as smoke. So, if smoke has to be given a matter of substance then it is can be categorized as a Colloid present in gaseous phase. Smoke is a solid which contains minute particles of dust which is homogeneously dispersed in the air.
You can use a separating funnel. The person will go the top and the water to the bottom.
I mostly believe in between D and B beacuse K3po4 and caco3 is not an element equation
C. 2Fe2O3 would be the correct answer!