Answer:
A reduction-oxidation (redox) reaction will occur.
Chlorine gas (Cl2) will accept electrons to form Cl- ions.
The Iron(II) ions (Fe2+) will lose electrons to form Fe3+ ions. (Iron (III) ions)
Fe2+ ions are green, while Fe3+ ions are yellow,
so the observation will be the solution turning from green to yellow.
Explanation: see attachment below
D Cobalt
Explanation:
The volume of the sphere is 40 -25 = 15 cm^3
Density = mass/volume = 133 gm / 15 cm^3 = 8.87 gm/cm^3
which corresponds to Cobalt from the chart
O 4
C 1
1 sodium
3 H
Products
4 O
1 C