1124 
Sulphurous acid and mercuric chloride at 30°. 
Quality of light 
‚ Time of 
Mercurous | 
chloride form- 
| reaction | ed in grams | 
1) Sunlight | 270’ 0.11328 
Darkness 270 0.10148 
2) Sunlight 120’ 0.02832 
Darkness 120’ 0.02242 
3) Sunlight 240’ 0.05592 
Darkness | 240’ 0.04394 
4) Diffused light | 250’ 0.04876 
Darkness | 250’ 0.04421 
5) Diffused light | 280’ 0.11185 
Darkness | . 280’ 0.10232 
50 c.c 
Volume of solution 
50 c.c. = HgCl, and 20 c.c. 
(1.25 factor) H,SO; 
cic: a HgCl, and 20 c.c. 
H,SO, 
Do 
Do 
N 
“10 
(factor 1.25) H,SO; 
HgCl, and 20c.c. 
A solution of sodium hypophosphite slowly reduces a solution of 
mercuric chloride. The reaction takes place according to the following 
equation : 
NaH,PO, + 4 HgCl, + 2 H,O = 4 HgCl + NaCl + HCI + H,PO,,. 
The reaction is markedly accelerated by light as will be evident 
from the following observations, which were carried out at 30°. 
Sodium hypophosphite and mercuric chloride. 
Quality of light 
1) Sunlight 
Darkness 
2) Sunlight 
Darkness 
3) Sunlight 
Darkness 
4) Diffused light 
Darkness 
5) Diffused light | 
Darkness 
Time of Amount of HgCl 
reaction formed in grams 
} 48° | 0.03304 
48 (0.02596 
125’ | 0.09834 | 
125’ | 0.07638 | 
160 0. 12862 
160’ 0.09654 
50’ 0.02854 | 
50’ 0.02558 | 
| 180° 0.12895 | 
180’ | 0.10321 | 
25 c.c. hypophosphite solution sl 
Volume of Solution 
10 
(factor 0.981) and 10 c.c. = Hegcly 
Do 
| | 25 cc. same hypophosphite solu- 
| \ tion and 20 c.c. 10 mercuric chloride. 
25 c.c. same hypophosphite solu- 
tion and 10 c.c. — mercuric chloride 
10 
25 c.c. same hypophosphite solu- 
tion and 20 c.c. = HgCly 
