How did the balloon inflate?

Title:How didi the balloon inflate?
To do this experiment we needed: 

• Vinegar 
• Baking soda 
• Paper funnel 
• A bottle 
• A balloon 
• spoon 

How we did the experiment
First we put the vinegar in the bottle.
Next we put the baking soda in the balloon with the paper funnel.
Then we fitted the balloon to the mouth of the bottle
After that we shook the baking soda out of the balloon in to the bottle.
When the baking soda mixed with the vinegar there was a chemical reaction.A gas called carbon dioxide was formed.The gas filled up the balloon.