Answer:
B. Soap solution
Explanation:
Hardness of water refers to the degree of calcium and magnesium in the water. In other words, hard water contains excessive mineral contents. The degree of hardness of a water body can be measured using the SOAP TEST KIT.
Due to the formation of insoluble minerals, soap forms an exvessive substance in the presence of hardwater because the particles or minerals contained in the water is reacting to form something insoluble. Hence, a SOAP test kit can be used to test the hardness of water.
Answer:
9.606 grams of citric acid are present in 125 mL of a 0.400 M citric acid solution.
Explanation:
Molarity : It is defined as the number of moles of solute present in one liter of solution. Mathematically written as:

Moles of citric acid = n
Volume of the citric acid solution = 125 mL =125 × 0.001 L= 0.125 L
(1 mL = 0.001L)
Molarity of the citric acid solution = 0.400 M

n = 0.400 M × 0.125 L = 0.05 moles
Mass of 0.05 moles of citric acid :

9.606 grams of citric acid are present in 125 mL of a 0.400 M citric acid solution.
Answer:
m= 6.9905 = 7 g
Explanation:
The formula is m= M.n
m= mass (g), M= Molar mass (g/mole), n= moles (moles)
Molar mass of Cu is 63.55
=) m= 63.55*0.11
m= 6.9905 = 7 g