Since the mole ratio is 1 to 1 for this reaction, you can just use M1V1 = M2V2 to solve, given that 1 refers to HBr and 2 refers to LiOH.
M1 = ?
V1 = 0.40 L
M2 = 0.50 M
V2 = 0.20 L
M1(0.40) = (0.50)(0.20)
Solve for M1 —> M1 = (0.50)(0.20)/0.40 = 0.25 M HBr
The correct option is A.
The chemical equation given above is an endothermic reaction. An endothermic reaction is a type of reaction which absorb heat from the environment. An endothermic reaction needs heat to occur, therefore, increasing the temperature of such a reaction will favor the formation of more product and the equilibrium of the reaction will shift [forward] to the right, which is the product side.
Answer : The value of 
of the weak acid is, 4.72
Explanation :
First we have to calculate the moles of KOH.
Now we have to calculate the value of of the weak acid.
The equilibrium chemical reaction is:
Initial moles 0.25 0.03 0
At eqm. (0.25-0.03) 0.03 0.03
= 0.22
Using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
![pH=pK_a+\log \frac{[HK]}{[HA]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BHK%5D%7D%7B%5BHA%5D%7D)
Now put all the given values in this expression, we get:
Therefore, the value of of the weak acid is, 4.72
A because b is for photosynthesis
No, some impurities may alter the observed effects of a chemical reaction.. during a reaction other products may be produced, they may alter the MP or BP of the pure substance.
