From the following, how many compounds contain at least one secondary alcohol? 

Given below are two statements:
Statement I: Dimethyl ether is completely soluble in water. However, diethyl ether is soluble in water to a very small extent.
Statement II: Sodium metal can be used to dry diethyl ether and not ethyl alcohol.
In the light of the given statements, choose the correct answer from the options given below:
A parallel beam of light travelling in air (refractive index \(1.0\)) is incident on a convex spherical glass surface of radius of curvature \(50 \, \text{cm}\). Refractive index of glass is \(1.5\). The rays converge to a point at a distance \(x \, \text{cm}\) from the centre of curvature of the spherical surface. The value of \(x\) is ___________.
\(X\) is the number of geometrical isomers exhibited by \([\mathrm{Pt(NH_3)(H_2O)BrCl}]\).
\(Y\) is the number of optically inactive isomer(s) exhibited by \([\mathrm{CrCl_2(ox)_2}]^{3-}\).
\(Z\) is the number of geometrical isomers exhibited by \([\mathrm{Co(NH_3)_3(NO_2)_3}]\). Find the value of \(X + Y + Z\). }
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).
