CHEMISTRyY Review Part-2

8. -All alkaline earth metals react with N2 gasat high temperature ( True)

    -Alkaline earth metals have high boiling points than alkaline metals. Therefore second statement is also correct.

    -Second ionization energy of alkaline metals are higher than that of alkaline earth metals. Therefore third statement is also correct.

    -Be(OH)2 and Mg(OH)2 are not strong bases as they do not dissociate completely in aqueous medium. Therefore this statement is false.

    - Down the first group solubility of their hydroxides increase. Therefore this is also true. 

     (Answer- 4)

9. Number of protons in Lithium= 3

    Effective nuclear charge is charge of nucleus felt by outer electrons. Due to electrons in 1n energy level,(they neutralize some amount of charge) charge felt by outer electrons are slightly lower than +3 (Answer – 2)

10. When some O2 is added to mixture at equilibrium some amount of O2 join with SO2 to form SO3. Therefore amount of SO2 become less than initial value when equilibrium is reestablished.  (Answer- 3)

12. Energy in 1 *10^20 photons = 6.626Js × (3×10⁸ ms^-1)

                                                              (470×10^-9  m)

                                                       = 7.1s//  (Answer- 2)

13.               ΔG = ΔH -TΔS           - Reaction is spontaneous until ΔG < 0. When temperature increase,

                                                        -If ΔS is negative (-TΔS) value increase positively.

                                                        -If ΔS is positive (-TΔS) value increase negatively.

     Therefore for ΔG to become positive from a negative value, initially ΔH, ΔS & ΔG must be negative. (Answer -2)

17. Rate constant is only dependent on temperature. Therefore no matter the concentration of reaction rate constant remain same (Answer- 1)