1118 
in all the instances studied i.e. for equal times of exposure, the 
change is much more rapid in sunlight than in diffused light. 
It has been found out that a solution of a nitrite slowly acts upon 
a solution of iodine and that the change is greatly accelerated by 
sunlight; the change never proceeds to completion, since it is reversible 
Na NO, + I, + H,O 2 Na NO, +- 2 HI. 
Moreover the hydriodie acid formed acts on the nitrite. 
Pure sodium nitrite was prepared by the double decomposition 
between silver nitrite and sodium chloride (Ray & Duar, Trans. 
Chem. Soc. 1913, 108, 10) and dissolved and standardised. 
The standard sodium nitrite solution was mixed with iodine and 
exposed as usual in stoppered bottles. (See table p. 1117.) 
Hydrazine hydrochloride and iodine. 
Time of | Amount of | Unchanged | 
exposure iodine added, iodine | Volume of Solution 
Quali-y of light 
1) Sunlight =| 255 | 0.1270 0.01066 | ES A (Factories) 
Darkness AC 256° Iecoriz0 | OLoles In 
| and 10 c.c. 10 iodine. 
2) Sunlight | 290 Do 0.00858 
Darkness 290’ | Do 0.01475 | me 
3) Diffusedlight| 240’ | Do 0.01712 | 
Darkness 240’ Do 0.01875 | | oh 
4) Diffused light | 70’ (0.0635 0.00964) li ioe. galt solutions 
Darkness 70’ Do 0.01028 | DCE: " iodine, 
5) Diffused light 135’ | Do 0.00488 
Darkness 135’ | Do 0.00642 | is 
Hydroxylamine hydrochloride and iodine. 
1) Sunlight | 258°. | 0.1270 0.00758 | Ae Onde NCI eee 
Darkness = 1255! 0.1270 0.01295 | | tor) and 10 c.c a iodine. 
2) Sunlight 45’ 0.0635 0.00671 10 cc. salt solution and 
Darkness 45! Do 0.00923 3 CC. al iodine. 
3) Diffused light 15! Do 0.00651 
Darkness 15 Do 0.00747 | ie 
4) Diffused light 39 0.03175 0.00051 10 feel salt solution tant 
Darkness 39’ 0.03175 0.00077 i ce. sf iodine. 
10 
