Answer:

Explanation:
pH is derived from the concentration of hydronium ions in a solution. Hydrocyanic acid is HCN.
First, we shall figure out the moles of HCN:

If HCN was a strong acid:
HCN has a 1:1 ratio of H+ ions, the moles of H+ is also the same.
To find the molarity, we now divide by Liters. This gets us:

Finally, we plug it into the definition of pH:
![pH = -log[H^{+} ]](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH%5E%7B%2B%7D%20%5D)


However, since HCN is a weak acid, it only partially dissociates. The
of HCN is
.
![K_a = \frac{[H^+][A^-]}{[HA]}](https://tex.z-dn.net/?f=K_a%20%3D%20%5Cfrac%7B%5BH%5E%2B%5D%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
We can use an ice table to determine that when x = H+,

![[H^+] = 8.83*10^{-6}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%20%3D%208.83%2A10%5E%7B-6%7D)
![pH = -log[H^{+} ]](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH%5E%7B%2B%7D%20%5D)


Answer:
Can either be a solid, a liquid or a gas
Explanation:
A solvent can either be a solid, liquid or a gas. It is the carrier medium in a solution. It is the one in which the solute is dissolved.
Although quite unusual, a solvent might also be a solid. An important application of this can be seen in the production of alloys. Alloys are mixture of metals. To produce let’s say an alloy containing just two metals, the use of a solid solvent is needed. Here, one of the two metals is known as the base metal. It is this base metal that will serve as the carrier medium for the other metal
I think its chemical properties sorry if i get it wrong
Answer:
A) double replacement
Explanation:
Chemical equation:
NaCl +CaS → Na₂S + CaCl₂
Balanced chemical equation:
2NaCl +CaS → Na₂S + CaCl₂
The given reaction is double replacement reaction in which cation and anions of each reactant exchange with each other.
Double replacement:
It is the reaction in which two compound exchange their ions and form new compounds.
AB + CD → AD +CB
Other options are incorrect because,
Synthesis reaction:
It is the reaction in which two or more simple substance react to give one or more complex product.
AB → A + B
Single replacement:
It is the reaction in which one elements replace the other element in compound.
AB + C → AC + B
Decomposition reaction:
It is the reaction in which one reactant is break down into two or more product.
AB → A + B