Here's why:

* Lead II nitrate (Pb(NO3)2) is a white crystalline solid.

* When dissolved in water, it dissociates into lead(II) ions (Pb²⁺) and nitrate ions (NO₃⁻).

* Neither of these ions absorbs visible light, so the solution appears colorless.

However, it's important to note that lead II nitrate solutions are often slightly acidic due to hydrolysis of the lead(II) ions. This acidity might cause a very slight yellowing over time if the solution is exposed to air and light.