Using some of the following reagents, describe the preparation of 500 mL, pH 7 citric acid 1.8 M citric acid
1.2 M sodium dihydrogen citrate
1.5 M sodium hydrogen citrate
0.8 M sodium citrate
0.1 M HCl
0.1 M NaOH
Citric acid: Ka1=7.4 x 10-4, Ka2=1.7 x 10-5, Ka3=4.0 x 10-7

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b

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.

the answer is symmetrical : )