Answer: -
60 mL of potassium chloride 20% should be diluted to prepare 480 ml of potassium chloride 2.5%
Explanation: -
Volume of potassium chloride solution = 480 mL
Percentage of potassium chloride = 2.5%
Amount of Potassium chloride = 
x 480 mL
= 12 mL
Let the required amount be R.
20 % of R = 12 mL.
x R = 12mL
R = 60 mL.
Thus, 60 mL of potassium chloride 20% should be diluted to prepare 480 ml of potassium chloride 2.5%
When it has been disproven
Answer:
hydrated ferric oxide is ferric hydoxide sol and is positively charged. When aqueous solution of NaCl is added to it,the Cl- ions neutralise the positive charge on the sol particles. In the absence of charge, brown precipitate is formes due to colloids can be coagulation of particles.Nov 11, 2020
Explanation: hope this help
I may be totally wrong but I’ll make a guess to it being thermodynamics.
You get 42 when you multiply 6 & 7.
