Quick LAB 10 min
Compounds
Procedure IE.1d
1. Place 4 g of
compound A in a
clear plastic cup.
2. Place 4 g of compound B in a
second clear plastic cup.
3. Observe the color and texture
of each compound. Record
your observations.
4. Add 5 mL of vinegar to each
cup. Record your observations.
Analysis
1. What physical and chemical
differences between the two
compounds did you record?
How do physical properties and
chemical properties differ?
2. Vinegar reacts with baking soda
but not with powdered sugar.
Which of these compounds
is compound A, and which is
compound B?

answer: - first one is the correct answer. .

explanations: - potassium sulfide is and cobalt(ii) chloride is .

charge on k is +1, charge on s is -2, charge on co is +2 and charge on cl is -1.

in a double replacement reaction the ion exchange takes place. in general the reaction looks like:

if one of the product is insoluble as per solubility rules then a precipitate of it is formed.

when we mix the aqueous solutions of potassium sulfide and cobalt(ii) chloride then chloride ion goes with potassium ion and sulfide ion goes with cobalt ion and the balanced equation is written as:

k and cl has equal charges, similarly co and s has equal charges and hence no subscripts are used for the product side.

as per the solubility rules, cos is insoluble and so it's precipitate is formed.

looking at the given choices, first choice is correct.