I have written this code to change colour of different labels through different buttons
 I am new to app development, just got stuck up in pretty basics:  
-(IBAction)ButtonPressed:(id)sender
{
    UIButton *btn=sender;
    if(btn.tag==1)
    {
        lbl1.text=@"";
        lbl1.backgroundColor=[UIColor redColor];
    }
    if(btn.tag==2)
    {
        lbl2.text=@"";
        lbl2.backgroundColor=[UIColor greenColor];
    }
    else if(btn.tag==3)
    {
        lbl3.text=@"";
        lbl3.backgroundColor=[UIColor magentaColor];
    }
    else if(btn.tag==4)
    {
        lbl4.text=@"";
        lbl4.backgroundColor=[UIColor blueColor];
    }
    else if(btn.tag==5)
    {
        lbl5.text=@"";
        lbl5.backgroundColor=[UIColor brownColor];
    }
}
After writing the code the colour of label one is only getting changed. I have connected all the elements through storyboard though
                        
Try it like this
Or Simply
Also check the tags of the buttons.