Given Information:

Mole fraction of substance A: 0.05
Molarity of substance B: 7 M
Density of the solution: 1.14

Calculation:

To find the molarity of substance A, we can use the relationship between mole fraction, molarity, and density of the solution.

Mole fraction of A (XA) can be defined as the ratio of the number of moles of A to the total number of moles in the solution. Mathematically, it can be expressed as:

XA = moles of A / (moles of A + moles of B)

Given that the mole fraction of A is 0.05, we can rewrite the equation as:

0.05 = moles of A / (moles of A + moles of B)

Since the mole fraction is given, we can assume a total volume of the solution to be 100 mL in order to simplify the calculations.

Step 1: Calculation of moles of B:

The molarity of substance B is given as 7 M. Molarity is defined as moles of solute per liter of solution. Therefore, the moles of B can be calculated using the following formula:

moles of B = molarity of B * volume of solution

Assuming a total volume of 100 mL, the volume of solution can be converted to liters:

Volume of solution = 100 mL * (1 L / 1000 mL) = 0.1 L

Now, substituting the values into the formula:

moles of B = 7 M * 0.1 L = 0.7 moles

Step 2: Calculation of moles of A:

We can rearrange the equation for mole fraction to solve for the moles of A:

moles of A = XA * (moles of A + moles of B)

Substituting the given values:

moles of A = 0.05 * (moles of A + 0.7)

Expanding the equation:

moles of A = 0.05 * moles of A + 0.05 * 0.7

Simplifying the equation:

0.95 * moles of A = 0.05 * 0.7

moles of A = (0.05 * 0.7) / 0.95 = 0.03684 moles

Step 3: Calculation of molarity of A:

Molarity is defined as moles of solute per liter of solution. Therefore, to find the molarity of A, we need to divide the moles of A by the volume of the solution.

Assuming a total volume of 100 mL, the volume of solution can be converted to liters:

Volume of solution = 100 mL * (1 L / 1000 mL) = 0.1 L

Now, substituting the values into the formula:

Molarity of A = moles of A / volume of solution

Molarity of A = 0.03684 moles / 0.1 L = 0.3684 M

Conclusion:

The molarity of substance A in the solution is 0.3684 M.