

44. On the retardation and acceleration in the dissolution 
of Mercury in Nitric Acid in the presence of minute 
traces of Ferric Nitrate and Manganous Nitrate, 
By P.C. Ray, D.Sc. 
Since the communication of my first paper on mercurous nit- 
rite to this Society (vide oe Asiatic Society of Bengal, 1896, 
Vol. Ixv, Part ii, No. 1) I have often “yr oceasion to prepare 
this compound in quantity for studying its many reactions. I 
have often been struck with the eta rei fact that samples of 
nitric acid have now and then failed to yield mercurous nitrite. 
Of late I have been busy investigating into the causes of this 
curious anomaly. It has now transpired that mere traces of iro 
manganese salts, the litter probably derived from the bottles 
Tait, have a marked influence in the dissolution - mercury 
and presumably of copper and other metals in nitric a 
view to throw light on this point, several prpeninnnia 
have already been taken in hand. ‘Ihe modus operandi is as fol- 
lows: Three beakers of about 55 c.c. capacity are arranged side 
by side. Ten c.c. of freshly distilled nitric acid of 1:40 sp. gr. are 
introduced into each, an c.c. of ferric ayer solution (1 e.c. 
=0°0012 Fe,0,) added to one, and . of manganous nitrate 
solution a c.c. =0'0954 ¢g. Mn,O0,) to nee ay while the third 
beaker contained unoontaninated acid for comparison. The acid 
was then diluted with 4U c.c. of water, and 10 grams of mercury 
poured into each beaker 
The details of one experiment are given below. The reaction 
“ seede ith the iron solution gave indications of crystals after 
2 hours is ‘50 minutes only ; but none appeared at all in the one 
“ seeded” witli manganons nitrate. The quantities of mercury 
dissolved were 2°14 g., 1°72 g, 2°50 g., respectively.! 
t has, however, been noticed that if, instead of the a 
the sulphates of the respective metals be substituted even in more 
diluted conditions, the dissolution of we tll as also the Siviitaie 
of mercurous nitrite, are considerably acceler 
am engaged in further investigation of this new and prom- 
ising subject. 

Cf. The interaction of copper and nitric acid in presence of metallic 
‘tail (“ Journ. Chem. Soc. Transactions,” June 1908, p. 1162). 
