115 
N . : Mn . : 
AY LON Ce: = malonie acid and 5 e.e. — sodium selenite, selenium 
2) 
separates after 140’ minutes’ exposure to sunlight. 
5) 10) Gc; = malie acid and 5 cc. 7 sodium selenite, selenium 
separates after 660’ minutes’ exposure to sunlight. 
Here also it bas been shown that oxidizing agents (e.g. K Mn O,, 
Nas, O,, H, O, ete.) markedly accelerate these reactions. Hence light 
and oxidizing agents play the same role of positive catalyst in these 
reductions of sodium selenite. 
Moreover, it has been observed that the oxidizing action of pot- 
assium permanganate on oxalic acid, tartaric acid, citrie acid, malonic 
acid, malie acid, lactic acid, ete. is markedly accelerated by light. 
A. Potassium permanganate and oxalic acid. 
A OO. 
N en . 
ORE: oxalie acid and 5 c.e. Tr KMnO,. Mixture becomes 
colourless i.e. KMnO, completely disappears after 
Sunlight Diffused light Darkness 
2'—30" 3 —50" 8'-—40" 
AT 
N yi : 
2) 20 ee. — oxalic acid and 10 cc. — KMnO, 
10 10 
SO Heo 105 
B. Permanganate and Tartaric acid. 
N T 
1) 10 cc. — tartaric acid and 5 c.c. Ta KMnO, becomes colour- 
less after 
Sunlight Diffused light Darkness 
lj 0 Bb " 8’ 
dN. : 
Then to the clear mixture 5 cc. Th KMnO, was added in each 
bottle; becomes colourless after 
Sunlight Diffused light Darkness 
2'— 30" 3'—50" 5'—45. 
N 2 N 
De id CC. a tartaric acid and 5 c.e. Th KMnO, colour disappears 
after 
3'—40! 4'—50" 7'—10". 
C. Permanganate and Citric acid. 
ENOR ‘ Ne : : 
1) AKO 5 citrie acid and 5 c.e. To KMnO, ; colour disappears 
after 
