paladin level 2 spell slots

Assuming multiclass with Paladin 3/Sorcerer 10/Warlock 7, he will have 11 levels of spell you have 16 slots now. One being level 6 which is not otherwise available to Paladins.

A level 1 spell fits into a level 1 spell slot, but a level 2 spell is too large for a level 1 slot – you can’t use lower-level spell slots to cast higher level spells.

A Paladin X/Warlock 2 will get a couple key invocations (like the devil sight trick) and will recharge their two highest paladin spell slots on a short rest, for divine smite or for whatever other purpose.