it was a three mark question, so what would the marks generally be located for? Because I feel like there wasn't too much to explain in this question
Yeah, good question, I missed that. Since they mentioned you should use an equation, you 100% need to list the lithium hydrolysis equation:
\[
\ce{
2Li_{ (s)} + 2H2O_{ (l)}\to 2LiOH_{ (aq)} + H2_{ (g)}
}
\]
(you may also write it with the lithium hydroxide as individual ions, that's fine, both are correct)
That'll get you one mark, and you should have been able to create this equation from looking at the electrochemical series. The next two will be about discussing problems with the cell. There are two safety concerns with the above equation:
1. Lithium hydroxide is a strong base, and so will be caustic (you should still be able to catch this in the ionic equation, as you'd have free hydroxide, which is the definition of a strong base - ionised hydroxide ions)
2. Hydrogen gas is generated, which is dangerous when uncontrolled
This would get you all three marks. However, if you also listed things such as:
3. Lithium hydrolysis is highly exothermic, and therefore dangerous
Or anything else I can't think of (ask me if unsure!), then they should each constitute one mark, as well.
VCAA can get a bit weird, so it might even be 3 marks distributed as - 1 for concern, 1 for equation, 1 for linking the two. But, my money would be on 1 for relevant equation, 1 for first concern, 1 for second concern.
EDIT: Now that I've said that, I reckon it is actually 1 for concern, 1 for equation, 1 for linking the two, because they haven't prompted you to give more than 1 reason, just to highlight why it might be unsafe with an equation. We'll know for sure when the assessor's report comes out, I guess