Lewis Theory

Q.

20 mL of 0.2 M NaOH is added to 50 mL of 0.2 M acetic acid to give 70 mL of the solution. What is the $pH$ of the solution? Calculate the additional volume $x$ (in mL) of 0.2 M NaOH required to make pH of the solution 4.74. The ionisation constant of acetic acid is $1.8\times {10}^{-5}$.

1. pH = 4.74, x = 4.568 mL

2. pH = 4.568, x = 4.83 mL

3. pH = 4.74, x = 4.568 mL

4. pH = 4.83, x = 4.83 mL

Q.

Which of the following is the strongest Lewis acid

1. BI₃

2. BBr₃

3. BCl₃

4. BF₃

Q. Solid BeH_2 and solid BeCl_2 are different in (a) hybridisation state (b) planarity of molecule (c) octet completion (d) polymerisatio

Q. Which compound form polymer due to H bond H2S HF

Q. 2. Which of the following solutions will exactly oxidize 25 ml acidic solution of 0.1 M iron (||) oxalate? (1) 25 ml of 0.1 M KMnO4 (2) 25 ml of 0.2 M KMnO4 (3) 25 ml of 0.6 M KMnO4 (4) 15 ml of 0.1 M KMnO4

Q. When a solution of benzoic acid was titrated with NaOH.the pH of the solution when half of the acid is neutralised was 4.2 .Dissociation constant of the acid is?

Q. Why does boron triflouride behave as a Lewis acid ?

Q. Number of moles of ferrous sulphate oxidized by 1 mole of potassium permanganate in acidic medium is: (1) 2/5. (2) 5/2. (3) 1/5. (4) 5.

Q. Calculate pH of a centimolar solution of hydrochloric acid .

Q. How are impurities in preparation of N2 from Nh4NO2 removed by passing through sulphuric acid and potassium Dichromate?

Q. 5.What is lewis acid base concept??

Q. 7. The ph of a solution obtained by mixing 100ml of 0.2 M Ch3COOH with 100ml of 0.2 M NaOH will be ?

Q.

An aqueous solution of a metal bromide $MB{r}_2$ of $0.05M$ is saturated with $H_{2}S$. What is the minimum $pH$ at which $MS$ will precipitate? Given $K_{sp}$ of $MS$ = $6.0\times {10}^{-21}$. Concentration of saturated $H_{2}S$ = $0.1M$ ($K_1$ of $H_{2}S$ = ${10}^{-7}$ and $K_2$ = $1.3\times {10}^{-1}C$)

1. 0.5

2. 0.26

3. 0.983

4. 0.38

Q. When a small amount of HCL os added to a buffer solution of acetic acid and sodium acetate- Ph increases H+ decrease Dissociation of acetic acid decrease

Q.

In which of the following reactions does $N{H}_3$ act as an acid ?

1. $N{H}_3$ + $H^{+}$ $⟶$ ${N{H}_4}^{+}$

2. $N{H}_3$ + Na $⟶$ $NaN{H}_2$ + $\frac{1}{2}$ $H_2$

3. $N{H}_3$ + HCl $⟶$ $N{H}_{4}Cl$

4. None of these

Q. 0.2 gm of a solution of mixture of NaOH and Na2CO2and inert impurities was first titrated with phenolphthalein and N/10 HCl 17.5 ml of HCl was required at the end point. After this methyl orange was added and 2.5 ml of same HCl was again required for next end point. Find out percentage of NaOH and Na2CO3 in the mixture.

Q. name the atom which has the highest ionization enthalpy and highest negative electron gain enthalpy

Q. 27. Why Bronsted acids are not lewis acids ?

Q. How acid or base increases the conductivity of pure water? Explain the process clearly.

Q. How phosphorous acid has basicity of 2 although it has 3 hydrogen ions?

Q.
Q. Compare the chemical reactivity of s-block elements.