1914-15.] The Eeaction between Sodamide and Hydrogen. 135 
appreciably in a vacuous tube at temperatures between 200° and 300°.* 
It is therefore clear that hydrogen is not without action on sodamide, if 
the gas be passed continuously over the solid. Only one explanation of 
this fact seemed reasonable — that the sodamide was being converted into 
sodium hydride by the action of the hydrogen, according to the equation 
NaNHg + H 2 = NaH + NH 3 . 
Since Moissan discovered that sodium, heated in hydrogen at 340°, forms 
the hydride, which is volatile at that temperature, and is, moreover, 
soluble in excess of the unchanged metal,f the explanation suggested 
became a probable one, and experiments were made to test it. 
At first it was attempted to employ the commercial sodamide ; but as 
this material always contains some sodium hydrate and cannot be trans- 
ferred from one vessel to another without reacting with atmospheric 
moisture, its use was abandoned. 
The small quantities of sodamide required were accordingly synthesised 
from pure sodium and pure ammonia. The loss of weight on heating each 
one of these samples in hydrogen was noted. It was then treated with 
water, and a measurement made of the hydrogen evolved. If formation of 
hydride has occurred, for every 1 5 ’02 grams which the sodamide loses in 
weight, 22’4 litres of hydrogen should be evolved, according to the 
equation 
NaH-f-H20 = .^W0-^H2 
on treating the product with water. To deprive the amide of nitrogen 
completely was not found possible, but this is immaterial, since the pre- 
sence of unchangred sodamide does not affect either estimation. 
An attempt was made to estimate the ammonia given off on heating 
in hydrogen, and to compare its amount with that of the hydrogen evolved 
on adding water. Although one result obtained in this way is given, the 
method was abandoned. A large reacting mass of hydrogen is required 
and the absorption of the greatly diluted ammonia becomes very difficult. 
The reactions were carried out in a specially made glass tube, about ten 
inches in length, and three-quarters of an inch in bore. It was lined 
on the inside with a thick roll of silver foil. In order to allow of the in- 
sertion of a silver boat, a ground-in stopper was fitted to one end of the 
tube. Leading tubes with stopcocks were fitted to the stopper and to the 
unstoppered end of the tube. The tube containing the roll of foil and the 
boat could be heated in an air-bath, with the ends projecting, and could 
be suspended from the arm of a balance and weighed. 
* Loc. cit, p. 508. t Oomptes Rendus, 1902, vol. cxxxiv, p. 71. 
