Methanol and ethanol are miscible in water due to

In which of the following reactions is a $2^o$ alcohol obtained as a product?

What is the $IUPAC$ name of the organic compound formed in the following chemical reaction?
Acetone $\xrightarrow[(ii) H_2O, H^{+}]{(i) C_2H_5MgBr, \text{dry Ether}}$ Product

An organic liquid $A$ containing $C$,$H$,and $O$ has a pleasant odour with a boiling point of $78\ ^\circ C$. On boiling $A$ with conc. $H_2SO_4$,a colourless gas is produced which decolourises bromine water and alkaline $KMnO_4$. One mole of this gas also reacts with one mole of $H_2$. The organic liquid $A$ is:

The conversion of $2-$methylpropan$-1-$ol to $2-$methylpropan$-2-$ol is:

Which is the best method to prepare cycloalkene from cyclohexanol?