Identify the reagents $$A$$ and $$B$$ respectively in the following reactions
$$C{ H }_{ 3 }COOH\underrightarrow { \quad \quad A\quad \quad  } C{ H }_{ 3 }COCl\underrightarrow { \quad \quad B\quad \quad  } C{ H }_{ 3 }CHO$$ 

1) $$SO{ Cl }_{ 2 },{ { H }_{ 2 } }/{ pd }-BaS{ O }_{ 4 }$$
2) $${ { H }_{ 2 } }/{ pd }-BaS{ O }_{ 4 },SO{ Cl }_{ 2 }$$
3) $$SO{ Cl }_{ 2 },{ H }_{ 2 }{ O }_{ 2 }$$
4) $$SO{ Cl }_{ 2 },Os{ O }_{ 4 }$$

Two cells are of the same emf. Their internal resistances are r₁ and r₂. They are connected in series across a resistor of resistance R. If the terminal potential difference across the cell of internal resistance r₁ is zero, then the value of R will be

1) r₁ + r₂
2) r₁ - r₂
3) r₂ - r₁
4)  r₁ . r₂/(r₁ + r_{2 )}

Eukaryotic cilium and flagellum are related with-

(1) Actin

(2) Myosin

(3) Tubulin

(4) Histone

The following ratio of hormonal concentration is required to induce callus to form shoot and root.

 1) Gibberellins à auxin
 2) Auxin à Cytokinin
 3) Gibberellins à Cytokinin
 4) Ethylene à auxins

A plane electromagnetic wave of frequency 20 MHz travels through a space along x direction. If the electric field vector at a certain point in space is 6 V m⁻¹, what is the magnetic field vector at that point?

1) 2×10⁻⁸T
2) 1/ 2×10⁻⁸T
3) 2T
4) 1 / 2T

A Uniform chain of length L and mass M is laying on a smooth table and ½ of its length is having down over the edge of the table. If g is the acceleration due to gravity, the work done to pull the hanging part on the table is:

1) mgL/18
2) mgL/8
3) mgL/9
4) mgL/32

One of the following is a co-enzyme

1) Tyrosinase
2) Trypsin
3) Nicotinamide adenine dinucleotide
4) Porphyrin

As it travels along the food chain the concentration
 of DDT

 (1) fluctuates randomly
 (2) stays constant
 (3) decreases
 (4) increases

When oil and water are into the same vessel, two layers are observed with the less dense oil on top. These two liquids are said to be:

1) hydrophilic
2) immiscible
3) hydrophobic
4) insoluble

A colloidal solution obtained by adding a mixture of stannous chloride and stannic chloride solution to a solution of gold chloride is known as

1)  cinna bar

2)  ruby

3)  fulminating gold

4)  purple of cassius