On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?

[Hint : NaCl + H2SO4 (conc.)->  NaHSO4 + HCl]

Because water molecules act as ligands and results in crystal Fleld splitting of d-orbitals of Cu2+ ion.

Nature pH Solution (a) (b) (c) (d) (e) Neutral Strongly alkaline Strongly acidic weakly acidic Weakly alkaline 7 11 1 4 9 D C B A E Arrangement of the pH in increasing order of hydrogen ion concentration is as follows: 11 < 9 < 7 < 4 < 1

(b) Yellow in acid and red in base. 

(d) colourless and pink

(a) basic, Answer is correct

It is a convex lens. No, when the object is placed close to a convex lens then the image formed is virtual which cannot be obtained on screen.

When excess of HCl is added, the colour of the final mixture will be colourless because the pink colour of sodium hydroxide is neutralised with the acid.

(i) The positively charged colloidal particles of Fe(OH)3 get coagulated by negatively charged Cl– ions provided by electrolyte sodium chloride.  (ii) The path of light is not visible when light is...

This is done to convert NH4 HCO3 usually present in large amounts along with (NH4)2 CO3 to (NH4) 2 Co3 NH4 HCO3 +NH4OH_------> (NH4 )CO3 H2O