I need help with chem again!

Test Preparation AP Test Preparation
1

<p>Can someone explain the following?</p>

<p>1) why are both reactions spontaneous?
I. Cl2 + 2Br= Br2 + 2Cl
II. Br2+ 2I = I2 + 2Br</p>

<p>2) Why are the carbon-carbon-carbon bond angles in CH3CHCH2 closest to 120 degrees?</p>

2

<p>1)
I. Standard reduction potentials. The potential for Cl2 to be reduced is higher than the potential for Br2 to be reduced, so Cl2 spontaneously becomes Cl-, and Br- becomes Br2
II. Same thing as I. Br2’s potential is greater than I2’s.</p>

3

<ol>
<li>The C’s are bonded like so: C-C=C. The central carbon is bonded to 3 different atoms, so it assumes a trigonal planar shape with respect to the H and 2 C’s, which has 120 degree bond angles.</li>
</ol>

4

<p>Comisar’s reduction potential explanation is correct - just note that if you are asked to rank halogens by activity in the MC section where no reduction potential table is available, you can answer the question equally well by comparing electronegativities.</p>