A scientific theory is a principle that can be falsified. The theory has to make strong statements about evidence. If the statements aren't strong, then the theory fits any evidence, and is unfalsifiable.
The question is incomplete, here is the complete question:
At 20°C the vapor pressure of benzene 
is 75 torr, and that of toluene 
is 22 torr. Assume that benzene and toluene form an ideal solution.
What is the mole fraction of benzene in the solution that has a vapor pressure of 38 torr at 20°C? Express your answer using two significant figures.
<u>Answer:</u> The mole fraction of benzene is 0.302
<u>Explanation:</u>
Let the mole fraction of benzene be 'x' and that of toluene is '1-x'
To calculate the total pressure of the mixture of the gases, we use the equation given by Raoult's law, which is:
We are given:
Vapor pressure of benzene = 75 torr
Vapor pressure of toluene = 22 torr
Vapor pressure of solution = 38 torr
Putting values in above equation, we get:
![38=[(75\times x)+(22\times (1-x))]\\\\x=0.30](https://tex.z-dn.net/?f=38%3D%5B%2875%5Ctimes%20x%29%2B%2822%5Ctimes%20%281-x%29%29%5D%5C%5C%5C%5Cx%3D0.30)
Hence, the mole fraction of benzene is 0.30
Net ionic equation
Cu²⁺(aq)+S²⁻(aq)⇒CuS(s)
<h3>Further explanation</h3>
Double-Replacement reactions. Happens if there is an ion exchange between two ion compounds in the reactant to form two new ion compounds in the product
In the ion equation, there is a spectator ion that is the ion which does not react because it is present before and after the reaction
When these ions are removed, the ionic equation is called the net ionic equation
For gases and solids including water (H₂O) can be written as an ionized molecule
Reaction
CuSO₄(aq)+Na₂S(aq)⇒CuS(s)+Na₂SO₄
ionic equation
Cu²⁺(aq)+SO₄²⁻(aq)+2Na⁺(aq)+S²⁻(aq)⇒CuS(s)+2Na⁺(aq+SO₄²⁻(aq)
spectator ions : 2Na⁺ and SO₄²⁻
Net ionic equation
Cu²⁺(aq)+S²⁻(aq)⇒CuS(s)
Answer:
The partial pressure of ammonia at equilibrium when a sufficient quantity of ammonium iodide is heated to 400°C Is 0.103 atm.
The correct option is A.
Explanation;
NH4I(s) ⇋ NH3(g) + HI(g)Kp = 0.215 at 400°C
NH4I(s)= 0.215
NH3(g)=0.103
HI(g)Kp=0.112
Therefore = 0.103 +0.112= 0.215
Therefore the partial pressure of ammonia at equilibrium is 0.103 atm
