How many bromide ions are present in 65.5 mL of 0.210 M GaBr₃ solution?

• A. 7.95x10²² ions
• B. 2.48x10²² ions
• C. 7.95x10²³ ions
• D. 6.50x10²³ ions
• E. 3.91x10²³ ions

Answer: (B)

Verified step by step guidance

1. First, understand that the molarity (M) of a solution is defined as the number of moles of solute per liter of solution. Here, the molarity of GaBr3 is given as 0.210 M, which means there are 0.210 moles of GaBr3 in 1 liter of solution.
2. Next, convert the volume of the solution from milliliters to liters. Since there are 1000 milliliters in a liter, divide 65.5 mL by 1000 to get the volume in liters.
3. Calculate the number of moles of GaBr3 in the given volume of solution using the formula: \( \text{moles of GaBr3} = \text{molarity} \times \text{volume in liters} \).
4. Recognize that each formula unit of GaBr3 contains three bromide ions (Br^-). Therefore, multiply the moles of GaBr3 by 3 to find the moles of bromide ions.
5. Finally, convert the moles of bromide ions to the number of ions using Avogadro's number, \( 6.022 \times 10^{23} \text{ ions/mole} \). Multiply the moles of bromide ions by Avogadro's number to find the total number of bromide ions present in the solution.