Answer
a. Final concentration = 0.100 M NaBr solution.
b. Final concentration = 4.50 % (m/v) $K_2SO_4$ solution.
c. Final concentration = 1.76 M $NaOH$ solution.
Work Step by Step
1. Write the dilution expression, and solve for the final concentration $(C_2)$
$C_1V_1 = C_2V_2$
$$\frac{C_1V_1}{V_2} = C_2$$
a.
2. Substitute the values and calculate the final concentration:
$$C_2 = \frac{(25.0 \space mL)(0.200 \space M)}{50.0 \space mL}$$
$$C_2 = 0.100 \space M$$
b.
2. Substitute the values and calculate the final concentration:
$$C_2 = \frac{(15.0 \space mL)(12.0 \space \% (m/v))}{40.0 \space mL}$$
$$C_2 = 4.50 \space \% (m/v)$$
c.
2. Substitute the values and calculate the final concentration:
$$C_2 = \frac{(75.0 \space mL)(6.00 \space M)}{255 \space mL}$$
$$C_2 = 1.76 \space M$$
