290 Journal of the Asiatic Society of Bengal [August, 1914. 



unc 



agent. It, therefore, appears that during the formation of lead 

 nitrite and lead nitrate a part of the peroxide is reduced to 

 lead monoxide. 



7. If a little of the yellow solution obtained by the action 

 of nitric oxide on lead dioxide in presence of water is shaken 

 up with the peroxide, its colour becomes fainter and after fil- 

 tration the residue on the filter-papar is found to contain lead 

 monoxide which may be readily separated from the unchanged 

 dioxide by treatment with dilute nitric acid. It, therefore, 

 follows that lead nitrate is formed, partly at least, by the 

 oxidizing action of lead peroxide en lead nitrite. 1 



Barium Peroxide. 



The apparatus used was the same as that employed in the 

 case of lead dioxide. On filtering the liquid in the flask after 

 passing nitric oxide through it a colourless solution was 

 obtained. This answered to the metaphenylene diamine test for 

 nitrites and gave a white precipitate of barium sulphate with 

 dilute sulphuric acid. On exposure to air it became turbid 

 on account of the presence of barium hydroxide which was 

 tormed when the mixture of barium dioxide and water was boiled 

 previously to passing the gas through it, and which uniting 

 with the carbon dioxide of the air formed barium carbonate. 

 After removing the nitrous acid with ammonium sulphate in 

 the usual way no red colouration was obtained on adding a solu- 

 tion of brucine in strong sulphuric acid. It, therefore, follows 

 that when nitric oxide is passed into water containing barium 



peroxide 



Quantitative 



Ba0 2 + 2NO = Ba(NO a ),. 



to confirm this result. 



Five cubic centimetres of the liquid obtained by passing nitric 

 oxide through water containing barium peroxide gave, on shak- 

 ing with concentrated sulphuric acid over mercury in a Crum 

 JNitrometer, 5-5 cc. of nitric oxide, measured over water at 



nfirrned in the following: manner 



rp , . ~— ■• ^^*"J-«.xxiC«j. ill wit) 1U1IUW1IL'4 IllfcUillOl I 



len cubic centimetres of the yellow solution were diluted to 50 cc. after 

 precipitation with sodium sulphate and filtration. The nitrite present in 

 of To- \ dlluted M quid was oxidized with N/10 potassium permangan- 

 ate (Jo cc.) containing free alkali, and after adding excess of potassium 



!r^i *• I f ated iodine was titrated with N/10 sodium thio-sulphate 

 (reduction factor 101). ' 



Aff™ u i y° lume of ^a-2 S* 3 solution required -2 15 cc. 



fewiSn f akm « U P 10 <*. of the yellow liquid with lead peroxide for a 

 lew minutes, and trasi.t-.inr, ;* ;~ +u~ * .i »__J_ _* iki„_«,l. 



manner 



St; f a squired was 22 1 cc. This was evidently due to the 

 oxidation of a part of the lead nitrite into lead nitrate bv the peroxide. 



