CO, + H2O –H^2 CO^3 The reaction is which type of chemical reaction?

Combination or synthesis reaction

Explanation:

The reaction is a combination or synthesis reaction.

Let us write the reaction equation:

         CO + H₂O →  H₂CO₃

A combination or synthesis reaction is one in which a single product forms from two or more reactants. The formation of a compounds from the union of their constituent elements falls into this category of reaction.

the millers tale is the answer.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.