1345 
in all the iiistances studied i.e. tor equal times of exposure, the 
change is niiich more rapid in sunlight tlian in ditfused light. 
It has been fonnd ont tliat a solntion of a uitrite slowly acts upon 
a solution of iodine and that the ehange is greatly accelerated by 
sunlight, the charige nevei* proceeds to completion ; since it is reversible 
Na NO, + I, + H,0 Na NO, + 2 Hl . 
Moreover the hydriodic acid formed acts on the nitrite. 
Pure sodium niirite was prepared by the doublé decoinposition 
between silver nitrite and sodium chloride (Rar & Dhar, Trans. 
Chein. Soc. 1913, 103 , 10) and dissolved and standardised. 
The Standard sodium nitrite solntion w^as mixed with iodine and 
exposed as usual in stoppered bottles. (See table p. 1344.) 
Hydrazine hydrochloride and iodine. 
Quality of light. 
Time of 
exposure 
Amount of 
iodine added 
Unchanged 
iodine 
Volume of Solution 
1) Sunlight 
255' 
0.1270 
0.01066 
1 10 C.C. ^ (factor 1.156) 
1 
' hydrazine hydrochloride 
Darkness 
255' 
0.1270 
0.01683 
1 N 
( and 10 c.c. iodine. 
/ 
2) Sunlight 
290' 
Do 
0.00858 
Do 
Darkness 
290' 
Do 
0.01475 
\ 
3) Diffused light 
240' 
Do 
0.01712 
Do 
Darkness 
240' 
Do 
1 0.01875 
( 
4) Diffused light 
70' 
0.0635 
0.00964 
1 10 c.c. salt solution and 
Darkness 
70' 
Do 
0.01028 
) 5 c.c. iq iodine. 
5) Diffused light 
135' 
Do 
0.00488 
Do 
Darkness 
1 135' 
Do 
j 0.00642 
1 
Hydroxylamine hydrochloride and iodine. 
1) Sunlight 
1 
255' 
0.1270 
0.00758 
Darkness 
255' 
0.1270 
0.01295 
2) Sunlight 
45' 
0.0635 
0.00671 
Darkness 
45' 
Do 
0.00923 
3) Diffused light 
75' 
Do 
0.00651 
Darkness 
75' 
Do 
0.00747 
4) Diffused light 
39’ 
0.03175 
0.00051 
Darkness 
39' 
0.03175 
0.00077 
lOc.c. hydroxylamine hy- 
drochloride N (1.128 fac- 
tor) and 10 c.c ~ iodine. 
I 10 c.c. salt solution and' 
j 5 c.c. iodine. 
j Do 
I 10 c.c. salt solution and 
i 2.5 c c. ^ iodine. 
