To how much water should 250 mL of 12 M hydrochloric acid be added to
produce a 4.0 M solution?

500 mL water

Explanation:

M1V1 =M2V2

M -molarity, V - volume of solution before adding water

M1 = 12MV1 = 250 mL

M2 = 4.0 M

12M * 250 mL = 4.0*V2

V2 = 12*250/4.0 = 750 mL of solution  should become after adding water

750 mL - 250 mL = 500 mL of water should be added

no starving yourself won't it will make you lose more weight what you need to do is find out what foods make you gain weight like bread and meats with fat on