Yes, you can use it but it will not charge any faster. Since you mentioned 1A and 2.4A rates, I'm guessing you're not talking about the various multi-voltage systems out there like Qualcomm's "Quick Charge" setup.
All standard chargers are rated at 5V and various amperage ratings. Even when using a higher current charger, it's the phone that determines how much current to pull from it. If the phone is only designed for 1A, then it'll pull a max of 1A from any charger rated AT LEAST 1A (a weaker charger would only allow that lower rate).
Multi-voltage systems like Quick Charge have a default safeguard that falls back to standard 5V charging. They have to negotiate with the phone to determine the proper charging voltages and current. If the phone can't perform that negotiation, then it'll just get standard charged.
Given the price of chargers these days, I say get the strongest one you can. It won't cost much more than a minimum one for your phone, but will last you longer with some future proofing.