If the mass of all of the products in a chemical reaction is equal to 100g then the mass of the reactants in that same reaction had to have had a mass of 100g this is due to the law of conservation of matter stating matter cannot be created or destroyed in a chemical reaction.
The mass of the water is 1.20 - 0.80 = 0.40 grams.
The % of water is (0.40 / 1.20 ) * 100 = 33 1/3%
I believe the correct answer would be that it feels slippery. Being slippery or soapy is one characteristic of a base. This due to the fact that it dissolves the oils and fatty acids from the skin. Other characteristics would be that it turns litmus paper blue and has a bitter taste.
Answer is: detergent is basic.
pH (potential of hydrogen) is a numeric scale used to specify the acidity or basicity an aqueous solution.
When pH is less than seven (pH<7), solution is acidic.
When is equal seven (pH = 7), solution is neutral.
When pH is greater than seven (pH > 7), like in this example, solution is basic.