Lead nitrate solution and sodium chloride solution taken in separate beakers. The beakers were weighed and mixed in one beaker and the beaker was weighed again. Does weight remains unchanged or not ? On what principle, the answer is based upon ?

Two beakers of capcatity 500 mL were taken one of these beakers labelled as "A" was filled with 400 mL water whereas the beaker labelled "B" was filled with 400 mL of 2 M solution of NaCl. At the same temperature both the beakers were placed in close containers of same material and same capacity as shown in the figure given below: At a given temperature, whihc of the following statement is correct about the vapour pressure of pure water and that of NaCl solution.

A student prepared solutions of (i)and acid and (ii) a base in two separate beakers. She forget to label the solutons and litmus paper is not available in the laboratory. Since both the solution are colourless, how will she distinguish between the two?

An appratus was set up as shown in the figure. It was observed that when an aqueous solution of HCl was taken in the beaker and the circit was closed, the bulb in the circuit began to glow, but it did not glow when the experiment was repeated with glucose solution. what could be the reason? Would the bulb glow if the same experiment is repeated with an aqueous solution of NaOH? why?

An appratus was set up as shown in the figure. It was observed that when an aqueous solution of HCl was taken in the beaker and the circit was closed, the bulb in the circuit began to glow, but it did not glow when the experiment was repeated with glucose solution. what could be the reason? Would the bulb glow if the same experiment is repeated with an aqueous solution of NaCl? why?

Three beakers labelles as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO_4 and NaCl were added to the breakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions containers in beaker A, and B, where in case of beaker C, the temperature of the solution falls. Which one of the following statements(s) is(are) correct? (i) In beaker A and B, exothermic process has occured. (ii)In beaker A and B, endothermic process has occured. (iii) In beaker C exothermic process as occured. (iv) In beaker C endothermic process has occured.