Why you think the chlorine atoms are on opposite sides of the beryllium atom?

The reason why the chlorines are on opposite sides of the beryllium atom is because their bonding pairs the electrons that connect the beryllium and chlorine through the covalent bond repel each other equally . because both bonding pairs are equally negative they repel to opposite poles of the beryllium atom to minimise the forces of repulsion

Hope that helps

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm