A deep blue colour is formed when `CuSO_4` solu-tion is treated with ammonia solution. What property of ammonia is associated with it. Why deep coloured solution is formed?

What happens when excess of ammonia is added to CuSO_4 solution?

What is the colour of the litmus solution when it is neither acidic nor basic?

Why does the colour of copper sulphate solution change when an iron nail is dipped in it?

An organic compound 'A' having molecular formula C_6H_6O gives a characteristic colour with aqeuous FeCI_3 solution. When 'A' is treated with CO_2 and NaOH at 400K under pressure 'B' is obtained. The compound B on acidification gives compound C which react with acetyl chloride to form D which is a popular pain killer. Deduce the structure of A, B, C and D.

Explain why When a solution of CuSO_4 is electrolytes with plantinum electrodes, the concentration of the electrolyte gradually diminishes but when copper electrodes are used no change in concentration of CuSO_4 occurs.

0.05 g of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in 50 ml of 0.5 MH_2SO_4 . The residual acid required 60ml of 0.5 M solution of NaOH for neutralization. Find the percentage composition of nitrogen in the given compound.

Form the pair of linear equations in the following problems and find their solutions (if they exist) by any algebraic method: A fraction becomes 1/3 when 1 is subtracted from the numerator and it becomes 1/4 when 8 is added to its denominator.Find the fraction.