can i use a1357 usb power adapter with my iphone x ?

As has already been mentioned, using an iPad charger (10 watt/2.1 amps or 12 watt/2.4 amps) is perfectly fine and will not damage your iPhone as the device and not the charger dictates how much current is pushed into the battery.

On the other hand, using an iPhone charger (5 watt/1amp) with an iPad is not recommended because 5 watts is not enough power to charge an iPad due to their much larger batteries.

You can absolutely use it with your iPhone. If you look at the listing for that adapter on Apple's online store, you'll see that they show it as compatible with iPhones. I've used nothing by iPad adapters with my iPhones for years as I don't want to carry two when I travel.

You can use an iPad charger to charge your iPhone. It will not damage the battery.