Neutral solution, hope this helps :)
The value of "d" is 80°
Explanation:
Cyclic quadrilaterals are the special group of quadrilaterals with all its base lying on the circumference of the circle. In other words, a quadrilateral inscribed in a circle is called a cyclic quadrilateral.
Cyclic quadrilateral are characterised by some special features such as
- Sum of opposite angles of a cyclic quadrilateral is always a supplementary angle.
- If one of the sides of a cyclic quadrilateral is produced, then the exterior angle so formed is always double of the corresponding interior angle.
Using the property 1
We find that since the quadrilateral is cyclic, opposite pairs must be supplementary
100°
+∠D must be equal to 180°
D=180°
-100°
=80°
Answer:

Explanation:
Assuming that all caculations are at normal pressure and -1.72°C :

Where
is the number of moles of hydrogen
is the mass of hydrogen
is the density of hydrogen