What positions do the sun, moon, and earth have to be in for the moon to be in the “new moon” phase?

When the Moon is between the Earth and the Sun, the bright side of the Moon is facing away from the Earth, and we have a New Moon (position A in the diagram below). The New Moon rises at sunrise, transits the meridian at noon and sets at sunset. The New Moon phase repeats every 29.531 days – one synodic month.

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.