1351 
Sulphurous acid and mercuric chloride at 30°. 
Quality of light 
Time of 
reaction 
Mercurous 
chloride form- 
ed in grams 
Volume of solution 
1) Sunlight 
270' 
0.11328 
1 50 c.c. HgCb and 20 c.c. 
Darkness 
270' 
0.10148 
) ^ (1.25 factor) H 2 SO 3 
2) Sunlight 
120 ' 
0.02832 
110 c.c. ^^ HgCl 2 and 20 c.c. 
Darkness 
120 ' j 
; 0.02242 
1 
H2SO3 
3) Sunlight 
240' 
0.05592 
1 Do 
Darkness 
240' 
0.04394 
4) Diffused light 
250' 
0.04876 
) 
Darkness 
250' 
0.04421 
S Do 
5) Diffused light 
280' 
0.11185 
^ 50 c.c. ~ HgCl 2 and 20 c.c. 
Darkness 
280' 
i 
0.10232 
1 
S (factor 1.25) H 2 SO 3 
A solution of sodium hj^pophosphite slowly rednces a solution of 
mercuric chloride. The reaction takes place according to the followmg 
equation ; 
NaH,PO, + 4 HgCl, + 2 H,0 = 4 HgCl + NaCl + HCl + H,PO,. 
The reaction is markedly accelerated bj light as will be evident 
frorn the following observations, which were carried out at 30°. 
Sodium hypophosphite and mercuric chloride. 
Quality of light 
Time of 
reaction 
Amountof HgCl' 
formed in grams 
Volume of Solution 
1) Sunlight 
48' 
0.03304 
N 
j 25 c.c. hypophosphite solution 
Darkness 
-48' 
0.02596 
i (factor 0.981) and 10 c.c. HgcU 
2) Sunlight 
125' 
0.09834 
j Do 
Darkness 
125' 
0.07638 1 
3) Sunlight 
160' 
0,12862 
i 
1 25 c.c. same hypophosphite solu- 
Darkness 
160' 
1 
0.09654 
j tion and 20 c.c. — mercuric chloride. 
4) Diffused light 
50' 
0.02854 
1 25 c.c. same hypophosphite solu- 
Darkness 
50' 
0.02558 
1 tion and 10 c.c. — mercuric chloride 
5) Diffufed light 
180' 
0.12895 
1 
) 25 c.c. same hypophosphite solu- 
Darkness 
180' 
0.10321 
j tion and 20 c.c. ^ HgCb 
