Why does lemon juice and baking soda have more pressure than vinegar soda?

This is not true. The reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid) produces more pressure than the reaction between baking soda and lemon juice (citric acid).

The chemical reaction between baking soda and vinegar is:

$$NaHCO_3(s) + CH_3COOH(aq) → CO_2(g) + H_2O(l) + CH_3COONa(aq)$$

This reaction produces carbon dioxide gas, which is responsible for the fizzing and pressure.

The chemical reaction between baking soda and lemon juice is:

$$NaHCO_3(s) + C_6H_8O_7(aq) → CO_2(g) + H_2O(l) + C_6H_5O_7Na(aq)$$

This reaction also produces carbon dioxide gas, but not as much as the reaction with vinegar. This is because citric acid is a weaker acid than acetic acid and does not react as completely with baking soda. As a result, the reaction between baking soda and lemon juice produces less pressure than the reaction between baking soda and vinegar.