Question

Okay so I have a couple of problems here that I don't think involve any math but I'm not sure on how to get an answer for any of these because I was not taught this type of question.
1. Which aqueous solution exhibits the largest freezing point depression?
A. 1.0 m KBr
B. .75 m C6H12O6
C. .5 m MgCl2
D. .25 m Ga2(SO4)3

2. Which metal reacts most vigorously with water at 25degree Celsius?
Na, Mg, K, Ca

3. Each of the following forms a colored aqueous solution except
Cr(NO3)3
Co(NO3)2
Cu(NO3)2
Zn(NO3)2

Answer 1

1. From the freezing-point depression equation: \(\large \Delta T=\color{red}i*m*K_f\)

We can see that it has to do with how many particles (\(i\)) are formed when those compounds are dissolved in water. The larger number of particles formed the larger the negative deviation from the normal freezing point of water. Figure out which dissociates into more particles (e.g. ions).

2. The metal that has more loosely held electrons - i.e. least ionization energy required.

3. This has to do with transitions of electrons amongst the \(d\) orbitals because these emit photons (light) in the visible range and appear colourful to us. One of these either has it's d orbitals filled (with electrons), or doesn't have any d electrons at all.