Two complexes [Cr(H₂O)₆]Cl₃ (A) and [Cr(NH₃)₆]Cl₃ (B) are violet and yellow coloured, respectively. The incorrect statement regarding them is :

A solution of sodium sulphate contains 92 g of Na⁺ ions per kilogram of water. The molality of Na⁺ ions in that solution in mol kg^$$-$$1 is :

0.5 moles of gas A and x moles of gas B exert a pressure of 200 Pa in a container of volume 10 m³ at 1000 K. Given R is the gas constant in JK^$$-$$1mol^$$-$$1, x is :

The one that is extensively used as a piezoelectric material is :