Sem4 Chemistry generic examination paper question with answer Write the formula of mercury tetrathiocyanato-cobaltate(III).Write the general formula of Alpha amino Write the structure of Zwitterions.acid.

 Q 1 :- Write the formula of mercury tetrathiocyanato-cobaltate(III).

Answer:-   Hg[Co(SCN)4]

Q 2 :- Which of the following is colored.
          (a) Fe^2+                 (b) Zn^2+               (c) Cu^2+                 (d)  Co^2+

Answer:- 
          (a) Fe^2+        (c) Cu^2+      and     ( d)  Co^2+        has unpaired electrons which can undergo electronic transitions   and hence show color.

Q3:- Write the general formula of Alpha amino acid.

Answer:- The general formula of amino acid is,  R-CH(NH₂)-COOH    or   NH2-C*H(R)-COOH.

 It consists of a basic amino group (-NH₂) and an acidic carboxyl group (-COOH) along with an organic R group (side chain) which is unique in each amino acid.

Q4:- Write the structure of Zwitterions.

A zwitterion is a molecule that has at least two functional groups: one having a positive charge and the other having a negative charge, with an overall charge of zero.

Amino acids are the most well-known zwitterions. They have an amino group (NH3+) which is positive and a carboxyl group (COO-) which is negative. The R group represents the side chain of different amino acids.
Q 5:- What happens when fats and oils are left exposed to moist air.

Answer:-
When fats and oils are left exposed to moist air they develop foul smell and sour test. It occurred when fats and oils are exposed for any length of time. It is due to Rancidification of fats and oils.
Rancidification caused by following reason,
(a) Oxidative Rancidification
(b)Hydrolytic Rancidification

Q 6 :- Write IUPAC name of K4[Ni(CN)4]

Answer:- Potassium tetracyanonickelate(0)

Q 7 :- Why transition elements are known as D block elements?

Answer:-
 Transition elements are those elements which have partially filled d-orbitals in their elementary form or in their commonly occurring oxidation states , also they are called d block elements because they have their valence electrons in one or more d-orbitals.
Note:- All transition elements are d-block elements but all d-block elements are not transition elements.
Example:- Zn,  Cd,  Hg  these elements are not transition elements because the orbitals of these elements are completely filled when they are in their ground state as well as in their general oxidation state.

Q 8 :- Why do the transition metal show variability in their oxidation state?

Answer:- 

Transition elements show variable state oxidation in their compounds because there is a very small energy difference in between (n-1)d and ns orbitals. As a result, electrons of (n-1)d orbitals as well as ns-orbitals take part in bond formation.

Q 8:- What is a zero order reaction?