Answer:- Mole ratio of D to A is 4:3.
Explanations:- Mole ratio for a chemical reaction is the ratio of the coefficients.
The given generic chemical reaction is:

The numbers written in front of each chemical species in the chemical reaction are their moles. For the given generic chemical reaction the coefficient of A is 3 and that of B is 1. So, the mole ratio of A to B is 3:1.
Similarly if we want to write the mole ratio of C to D then it is 1:4.
We are asked to write the mole ratio of D to A. So, like the other ratios, the mole ratio of D to A is 4:3 as the coefficient of D is 4 and A is 3.
Answer:
b. milk spoiling and c. firecrackers exploding
Explanation:
These are both chemical changes, the composition of them change when this happens and it cannot be reversed
<u>Answer:</u> The molar solubility of
is 
<u>Explanation:</u>
Solubility is defined as the maximum amount of solute that can be dissolved in a solvent at equilibrium.
Solubility product is defined as the product of concentration of ions present in a solution each raised to the power its stoichiometric ratio.
The balanced equilibrium reaction for the ionization of calcium fluoride follows:

s 2s
The expression for solubility constant for this reaction will be:
![K_{sp}=[Pb^{2+}][I^-]^2](https://tex.z-dn.net/?f=K_%7Bsp%7D%3D%5BPb%5E%7B2%2B%7D%5D%5BI%5E-%5D%5E2)
We are given:

Putting values in above equation, we get:

Hence, the molar solubility of
is 
Answer:
0.071L
Explanation:
From the question given, we obtained the following data:
Molarity of HCl = 2.25 M
Mass of HCl = 5.80g
Molar Mass of HCl = 36.45g/mol
Number of mole of HCl =?
Number of mole = Mass /Molar Mass
Number of mole of HCl = 5.8/36.45 = 0.159mole
Now, we can obtain the volume required as follows:
Molarity = mole /Volume
Volume = mole /Molarity
Volume = 0.159mole/ 2.25
Volume = 0.071L