1332 
Glycollic acid and bromine. 
Quality of light. 
Time of 
exposure 
■ Amount of 
bromine 
added in 
grams 
Unchanged i 
bromine 
Volume of solution 
a) Sunlight 
22' 
0.06035 
0.01234 
1 N 
f 50 c.c. glycollic 
1 acid and lOc.c. bro- 
Darkness 
22' 
0.06035 
0.04218 
1 mine water. 
b) Sunlight 
45' 
Do 
0.00597 
i Do 
Darkness 
45' 
Do 
0.02242 
1 
c) Diffused light 
25' 
Do 
0.02234 
Do 
Darkness 
25' 
Do 
0.04138 
) 
d) Diffused light 
50' 
Do 
0.01075 
j Do 
Darkness 
50' 
Do 
0.02105 
Sodi 
urn glycollate 
! and bromim 
a) Sunlight 
20' 
0.06035 
0.00584 
1 JV 
1 50 cc. sodium gly- 
1 collate and 10 c.c. bro- 
Darkness 
20' 
0.06035 
0.03345 i 
) mine water. 
b) Sunlight 
50' 
0.12070 
0.00952 
1 JV 
f 50 c.c. sodium gly- 
1 collate and 20 c.c. bro- 
Darkness 
50' 
0.12070 
0.06375 
) mine water. 
c) Diffused light 
55' 
Do 
0.02475 
( Do 
Darkness 
55' 
Do 
0.06231 
1 
d) Diffused light 
24' 
0.06035 
0.01375 
1 JV 
1 50 c.c. sodium gly- 
1 collate and 10 c.c. bro- 
Darkness | 
24' 
0.06035 
0.03205 1 
i 
' mine water. 
From a glance at the foregoing tables it will be clear that the 
reaction velocitj is greater with the salts than with the corresponding 
acids. Hence it can be inferred that the aetion of bromine takes 
place 011 the negative radicles (e.g. tartarate ions, oxalate ions etc.). 
It will be seen that oxalic acid and oxalates act most vigoroiisly. 
Moreover it will be seen that in these actions the “Reciprocity 
Law” holds good; (i.e. a photo-chemical change will be in general 
greater the greater the inlensity of light. If we denote by A — ^ B 
