How do you calculate 1ml of 0.1n sodium thiosulphate is equivalent to 23.79mg of cobaltus chloride?

To calculate the equivalent amount of cobalt(II) chloride for 1 mL of 0.1 N sodium thiOSulfate, you need to use the concept of normality and the equivalent weight of cobalt(II) chloride. First, determine the equivalent weight of cobalt(II) chloride (CoCl2), which is the molar mass divided by the number of moles of replaceable ions (in this case, 2 for Co^2+). Using the relationship between normality and equivalence, you find that 1 mL of 0.1 N sodium thiOSulfate provides 0.1 equivalents, and by calculating the corresponding mass of cobalt(II) chloride, you find it to be 23.79 mg.