Solution: 

If the solubilities are S₁, S₂, S₃ respectively, then the K_sp values for them are
For A₂B, K_sp = 4 S31 [A₂B ? 2A⁺ + B^2-]
For AB, K_sp = S22 [AB ? A⁺ + B^-]
For AB₃, K_sp = 27S43 [AB₃ ? A³⁺ + 3B^-]
Since the value of K_sp is same
∴ The correct order of solubilities is
AB > A₂B > AB₃.

Solution

Transition metals are less reactive than alkali metals because of their high ionization potential and high melting point. 

On moving from left to right of the periodic table for every period, electrons fill in the same shell or orbital, with the alkali metals having the least filled outermost shells, one electron, which equates to fewer protons in them.

Consequently, they have a lesser attraction power from the nucleus, whereas, the corresponding transition metals of the same period have more protons interacting with electrons at the same distance, far from the nucleus as the alkali metals.

The four energy level contains electrons in the s, p, d, and f orbitals. All you need to do is take the sum of the number of electrons and all four orbitals (s:2, p:6, d:10, f:14) to reach the correct answer of 32.

SOLUTION

We know that for Geometrical Isomer we need a double bond between carbon atom  (this restricts rotation) and carbon atom at two sides must be linked to two different groups.

SOLUTION 

Silver cannot replace H from HCl as it is placed at bottom of H in reactivity series, hence less reactive then H.

Solution

Greyish white metal which is a good conductor of electricity and heat and has a boiling point of $$920^\circ C$$ is zinc.

Solution

Acetophenone being ketone does not react with Tollen's reagent to give silver mirror

Solution

Strength of the solution $$=34 $$ g/L.
1 L (or 1000 mL) of the solution contains 34 g of $$H_2O_2$$
200 mL of the solution contains $$\dfrac{34}{1000} \times 200= 6.8 $$ g of $$H_2O_2$$

6.8g of $$H_2O_2$$ gives  $$\dfrac{32}{68} \times 6.8= 3.2$$ g of $$O_2$$

Solution

2Mg + O₂ → 2MgO₂

According to the above reaction,

28.6g(2mole) Mg Mg combine with 32g(1mole) of O₂ to give 80.6g(2mole) of MgO.

thus,

30g Mg will combine with 20g of O₂ to produce 50g MgO and 10g O₂ will remain unreactive.