Charging 1a device with.75a charger. Both 5v. Is it okay?

Charging 1a device with.75a charger. Both 5v. Is it okay?

Added (1). Its working but want to know. More specifically, it is iphone and blackberry charger.

It is okay, but not recommended.
Your device will charge slowly and may not charge at all if you are using it while charging. Your adapter may also overheat.
Otherwise, there will be no serious issues.

Yes,
It will just be 33% slower…/take one third more time.

The standard USB socket only gives 0.5A (eg PC socket)
and they are fine…

all early chargers were 0.5A, later ones were higher,
you can even get 'fast' ones at 2.0Amps

Don't worry about it.