Everytime i go to safari application it never works my unit is iphone5

Tap Settings > Safari then tap to Clear History & Website Data then restart your iPhone and try Safari.

Try reseting Safari. Close Safari completely from the multitasking window by double clicking the Home button and swiping up the Safari preview pane up until it disappears from the screen. You may have to look for the Safari pane by swiping side to side as there may be other panes there from other apps. Then go to Settings > Safari > Clear History and Website Data. Then do a forced restart. Hold down the Home and Wake/Sleep buttons at the same time for about 15-20 seconds until the Apple logo appears. Ignore the "Slide to power off" text if it comes up. You will not lose anything.