List of top Chemistry Questions

Preparation of ethers by acid dehydration of secondary or tertiary alcohols is not a suitable method. Give reason.

The reaction CH₃CH₂I + KOH(aq) $\rightarrow$ CH₃CH₂OH + KI is classified as

Draw the Lewis structures for the following molecules and ions: $H_2S$, $SiCl_4$, $BeF_2$, $CO_3^{2-}$ , $HCOOH$

The correct decreasing order of boiling point of hydrogen halides is

The following results are observed when sodium metal is irradiated with different wavelengths. Calculate (a) threshold wavelength and, (b) Planck’s constant

λ (nm)	500	450	400
v × 10^–5(cm s^–1)	2.55	4.35	5.35

What is the coordination entity formed when excess of aqueous $KCN$ is added to an aqueous solution of copper sulphate? Why is it that no precipitate of copper sulphide is obtained when $H_2S(g)$ is passed through this solution?

The ionisation potential is lowest for the

Draw the structures of all isomeric alcohols of molecular formula C₅H₁₂O and give their IUPAC names. (ii)Classify the isomers of alcohols in question 11.3(i)as primary, secondary and tertiary alcohols.

$ {{(C{{H}_{3}})}_{3}}CMgCl $ on reaction with $ {{D}_{2}}O $ produces

What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.

F^-
Ar
Mg²⁺
Rb⁺

(B) (a) Write chemical equations of the following reactions: (i) Phenol is treated with conc. $ HNO_3 $.
(ii) Propene is treated with $ B_2H_6 $ followed by oxidation by $ H_2O_2 / OH^- $.
(iii) Sodium t-butoxide is treated with $ CH_3Cl $.

Bromine monochloride, BrCl decomposes into bromine and chlorine and reaches the equilibrium:
$2BrCl (g) ⇋ Br_2 (g) + Cl_2 (g)$
for which K_c = 32 at 500 K. If initially pure BrCl is present at a concentration of 3.3 × 10^–3 mol L^–1, what is its molar concentration in the mixture at equilibrium?

8.8 g of monohydric alcohol added to ethyl magnesium iodide in ether liberates 2240 cm³ of ethane at STP. This monohydric alcohol when oxidised using pyridinium-chlorochromate, forms a carbonyl compound that answers silver mirror test (Tollens’ test). The monohydric alcohol is :

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

Discuss the shape of the following molecules using the VSEPR model:
BeCl₂, BCl₃, SiCl₄, AsF₅, H₂S, PH₃

Primary alkyl halide C₄H₉Br (a)reacted with alcoholic KOH to give compound(b).Compound(b)is reacted with HBr to give(c)which is an isomer of(a). When (a) is reacted with sodium metal it gives compound(d), C₈H₁₈ which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of(a)and write the equations for all the reactions.

Discuss briefly giving an example in each case the role of coordination compounds in:

biological systems
medicinal chemistry
analytical chemistry
extraction/ metallurgy of metals

Which of the following reactions will give the major and minor products?

The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 Scm^-1 . Calculate its molar conductivity.

The amount of solute (molar mass $ 60\text{ }g\text{ }mo{{l}^{-1}} $ ) that must be added to $180\, g$ of water so that the vapour pressure of water is lowered by $10\%$, is

Write equations of the following reactions:
(i)Friedel-Crafts reaction–alkylation of anisole.
(ii)Nitration of anisole.

(iii)Bromination of anisole in ethanoic acid medium.
(iv)Friedel-Craft’s acetylation of anisole.

The reaction between A and B is first order with respect to A and zero order with respect to B. Fill in the blanks in the following table:

Experiment	A/ mol L^-1	B/ mol L^-1	Initial rate/mol L^-1 min^-1
I	0.1	0.1	2.0x10^-2
II	-	0.2	4.0x10^-2
III	0.4	0.4	-
IV	-	0.2	2.0x10^-2

For the reaction,

{C O}_{(g)} + {C l}_{2 (g)} ⇌ {C O C l}_{2 (g)}

, then

K_{p} / K_{c}

is equal to:

(b) (ii) Which one of the following will have higher osmotic pressure in 1 M KCl or 1 M urea solution? Justify your answer.

Using the standard electrode potentials given below ,predict if the reaction between the following is feasible:
(a) Fe³⁺(aq) and I^- (aq)
(b) Ag⁺ (aq) and Cu(s)
(c) Fe³⁺ (aq) and Cu(s)
(d) Ag(s) and Fe³⁺(aq)
(e) Br₂(aq) and Fe²⁺(aq)