Venus is closer to the Sun than we are, so it's always been hotter, even without the greenhouse effect. Any water on Venus would be gaseous, leading to increased greenhouse effect, leading to hotter temperatures, leading to water molecules reaching the upper atmosphere where they could be hit by UV photons. Venus is too hot to have liquid water because it's too close to the Sun. Earth also had volcanic activity like Venus but because it is cooler, the water vapor could condense out of the atmosphere as rain and liquid water could exist on the surface. No runaway greenhouse effect because less gaseous water in the atmosphere.
Earth is at the right distance from the Sun to have liquid water.
Carbon dioxide During volcanic eruptions, both water and carbon dioxide are released. The oceans are the key. There is 60 times more CO 2 in the oceans than there is in the atmosphere. Eroded silicate rocks get washed into the ocean and the minerals get deposited on the ocean floor. They react with the dissolved CO 2 and form carbonate rocks like limestone.