Answer the following questions pertaining to the brown ring test for nitric acid :
Give a reason why the brown ring does not settle down at the bottom of the rest tube.

Answer the following questions pertaining to the brown ring test for nitric acid : State why the unstable brown ring decomposes completely on disturbing the test tube .

Which of the following salt will not give positive brown ring test?

A uniform solid cylinder of mass 2 kg and radius 0.2 m is released from rest at the top of a semicircular track of radius 0.7 m cut in a block of mass M = 3 kg as shown in Fig. The block is resting on a smooth horizontal surface and the cylinder rolls down without slipping. Based on the above information, answer the following questions: The speed of the point of contact of the cylinder with the block w.r.t. ground, when the cylinder reaches the bottom of the track is

Explain with the help of a balanced equation, the brown ring test for nitric acid.

Give reasons for the following - pertaining to the above laboratory preparation of nitric acid (i) concentrated hydrochloric acid is not used as a reactant in the laboratory preparation the complete apparatus in the laboratory preparation does not contain parts made of rubber or cork. , (iii) the reaction temperature is maintained below 200^(@)C (iv) at high temperatures the sodium sulphate or potasium sulphate formed , forms a crust and sticks to the glass apparatus .

The following questions pertain to the laboratory prepration of hydrogen chloride. Gas : Write the equation for its preparation ,menfioning the condition required . Name the drying agent used in the above preparation and give a reason for the choice. (iii State a safety precaution taken during the preparation of hydrochloric acid .

The diagram given below is a representation of a phenomenon pertaining to the nervous system. Study the diagram and answer the following questions: (i) Name the phenomenon that is being depicted. (ii) Give the technical term for the point of contact between the two nerve cells. (iii) Name the parts A, B, C and D. (iv) Write the functions of parts E and F. (v) How does the arrangement of neurons in the spinal cord differ from that of the brain.

Give reasons for the following : (i) Nitric oxide become brown on exposure to air

Salt (A) on heating gives a colourless neutral gas which supports combustion. From the aforesaid, flow diagram, answer the following questions. The basic radical of salt (A) and gas B both gives brown precipitate with Nessler's reagent.The composition of the brown precipitate is: