What is an ideal risk reward ratio when trading breakouts?

While this depends on various things, I'd say a minimum of 1:2 is required in such trades, if not higher. The higher the risk/reward, the more likely you want to continue it. Breakout trades with poor risk/reward will eventually make you lose money as the high failure rates and noise can whips you out of your positions. 

Well, there is no single answer to this question. Instead, RR depends on your trading style, trading time frame, volatility, etc.

For day trades, the reward could be 1.2-1.5 times the risk. For positional trades, it could be 2-4 or even 5 times the risk, depending on factors like conviction, holding period, etc.