After performing a dilution calculation, you determine you need 25.0 milliliters of an aqueous stock solution to make 100.0 milliliters of a new solution. how would this be prepared?

To solve this we use the equation, 

M1V1 = M2V2

where M1 is the concentration of the stock solution, V1 is the volume of the stock solution, M2 is the concentration of the new solution and V2 is its volume. 

We prepare the solution by measuring 25 mL of the stock solution in a graduated cylinder or by using a pipette. Then, put the stock solution in a 100mL of volumetric flask. Dilute it by adding distilled water up to the 100mL mark in the flask. It should be noted that the lower meniscus of the solution should be the point where you observe the volume. 

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.