14. A certain mass of an ideal gas occupies 250.0 cm3 at 20°C and 9.89 x 104 Pa. At what temperature (in °C) will it occupy 400.0 cm3 if the pressure remains the same?

A.(nh4)(2co3)is the correct answer 

Sorry i dont understand the question can you rephase it?

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts