The energy of an electron in the first Bohr orbit of hydrogen atom is $$-2.18 \times 10^{-18} \mathrm{~J}$$. Its energy in the third Bohr orbit is ____________.
$$\mathrm{Be}(\mathrm{OH})_{2}$$ reacts with $$\mathrm{Sr}(\mathrm{OH})_{2}$$ to yield an ionic salt.
Choose the incorrect option related to this reaction from the following :
Given below are two statements :
Statement I : Permutit process is more efficient compared to the synthetic resin method for the softening of water.
Statement II : Synthetic resin method results in the formation of soluble sodium salts.
In the light of the above statements, choose the most appropriate answer from the options given below:
$$\mathrm{KMnO}_{4}$$ is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute $$\mathrm{H}_{2} \mathrm{SO}_{4}$$. Number of water molecules produced for 2 molecules of $$\mathrm{KMnO}_{4}$$ is ___________.