I agree with the others. You would probably lose weight but is it entirely healthy to just eat soup and salad all the time. In my research, I learned the best way to lose weight is the combination of diet and exercise. Try researching a plan or program that best suits you.
I depends on what type of diet do you eat and the composition within the salad if its still healthy for you. If the dietary intake amount will be meet.
Just know if you do that you will lose weight but you will harm your metabolism. When you go back to eating normally you will gain all the weight back. So why not weight lift or bike and eat a little healthier!?
You would but not as fast as you would like as just doing this alone will take a long time and this alone won't eliminate your empty stomach feeling so you would cheat a lot here just to feel full and energized.
That's it? You're lacking essential nutrients. You need a lot more than that to survive. You will lose weight that way, but you'll look like you've lost too much. Try to eat lots of fruits, veggies, complex carbohydrates, and proteins and try to lower simple carbohydrates and fats:)