Chemistry-
General
Easy
Question
Tautomerism is the phenomenon in which two structural isomers differing in the relative positions of their atoms are spontaneously interconvertable and can exist in dynamic equilibrium. The two forms in tautomeric equilibrium are called tautomers of each other. The interconvertibility of tautomers is a chemical reaction which involves making and braking of bonds. Tautomers are true isomers, and either of the individual tautomeric forms may be isolated
In the keto-enoltautomerism of dicarbonyl compounds the enol form is preferred in contrast to the keto form, this is due to
- Rapid chemical exchange
- Group rearrangement
- Presence of carbonyl group on each side of the chain
- Resonance stabilization of enol form
The correct answer is: Resonance stabilization of enol form
Due to hydrogen bonding and resonance enol form is preferred in contrast
Related Questions to study
Physics-
In LR circuit (shown in figure), current is lagging by 
in phase with applied voltage, then select correct alternative :
In LR circuit (shown in figure), current is lagging by in phase with applied voltage, then select correct alternative :
Physics-General
Physics-
A metal rod of length, moving with an angular velocity v and velocity of its centre is v. Find potential difference between points A and B at the instants how n in figure. A uniform magnetic field of strength B exist perpendicular
to plane of paper :
A metal rod of length, moving with an angular velocity v and velocity of its centre is v. Find potential difference between points A and B at the instants how n in figure. A uniform magnetic field of strength B exist perpendicular
to plane of paper :
Physics-General
Physics-
Particle sticks to wooden loop, If particle reach at the lowest position for first time after time T. Then displacement of centre of mass of system in this time interval will be :
Particle sticks to wooden loop, If particle reach at the lowest position for first time after time T. Then displacement of centre of mass of system in this time interval will be :
Physics-General
Physics-
One end of a light rod of length 1 m is attached with a string of length 1m. Other end of the rod is attached at point O such that rod can move in a vertical circle. Other end of the string is attached with a block of mass 2kg. The minimum velocity that must be given to the block in horizontal direction so that it can complete the vertical circle is (g = 10 m/s2 )
One end of a light rod of length 1 m is attached with a string of length 1m. Other end of the rod is attached at point O such that rod can move in a vertical circle. Other end of the string is attached with a block of mass 2kg. The minimum velocity that must be given to the block in horizontal direction so that it can complete the vertical circle is (g = 10 m/s2 )
Physics-General
Physics-
Three point masses are attached by light inextensible strings of various lengths to a point O on the ceiling. All of the masses swing round in horizontal circles of various radii with the same angular frequency w (one such circle is drawn in the shown figure.) Then pick up the correct statement.
Three point masses are attached by light inextensible strings of various lengths to a point O on the ceiling. All of the masses swing round in horizontal circles of various radii with the same angular frequency w (one such circle is drawn in the shown figure.) Then pick up the correct statement.
Physics-General
Physics-
Two blocks of mass m1 and m2 (m1 < m2 ) are connected with an ideal spring on a smooth horizontal surface as shown in figure. At t = 0 m1 is at rest and m2 is given a velocity v towards right. At this moment, spring is in its natural length. Then choose the correct alternative :
Two blocks of mass m1 and m2 (m1 < m2 ) are connected with an ideal spring on a smooth horizontal surface as shown in figure. At t = 0 m1 is at rest and m2 is given a velocity v towards right. At this moment, spring is in its natural length. Then choose the correct alternative :
Physics-General
Physics-
A small bead of mass m = 1 kg is free to move on a circular hoop. The circular hoop has centre at C and radius r = 1 m and it rotates about a fixed vertical axis. The coefficient of friction between bead and hoop is µ = 0.5. The maximum angular speed of the hoop for which the bead does not have relative motion with respect to hoop, at the position shown in figure is : (Take g = 10 m/s2)
A small bead of mass m = 1 kg is free to move on a circular hoop. The circular hoop has centre at C and radius r = 1 m and it rotates about a fixed vertical axis. The coefficient of friction between bead and hoop is µ = 0.5. The maximum angular speed of the hoop for which the bead does not have relative motion with respect to hoop, at the position shown in figure is : (Take g = 10 m/s2)
Physics-General
Physics-
A particle is moving along an elliptical path with constant speed. As it moves from A to B, magnitude of its acceleration
A particle is moving along an elliptical path with constant speed. As it moves from A to B, magnitude of its acceleration
Physics-General
Physics-
In the figure shown a semicircular area is removed from a uniform square plate of side ‘ l ’ and mass ‘m’ (before removing). The x-coordinate of centre of mass of remaining portion is (The origin is at the centre of square)
In the figure shown a semicircular area is removed from a uniform square plate of side ‘ l ’ and mass ‘m’ (before removing). The x-coordinate of centre of mass of remaining portion is (The origin is at the centre of square)
Physics-General
Physics-
Consider the system shown in figure. Pulley, string and spring are ideal and Dm << M. Initially spring is in it’s natural length and both the blocks are at rest. (Assume that initially Dm was situated at origin). Maximum y coordinate of Dm in subsequent motion is xmg/k then value of x is
Consider the system shown in figure. Pulley, string and spring are ideal and Dm << M. Initially spring is in it’s natural length and both the blocks are at rest. (Assume that initially Dm was situated at origin). Maximum y coordinate of Dm in subsequent motion is xmg/k then value of x is
Physics-General
Physics-
A steel wire is rigidly fixed along diameter of aluminium ring of radius R as shown. Linear expansion coefficient of steel is half of linear expansion coefficient for aluminium, then the thermal stress developed in steel wire is: (aAl is linear expansion coefficient for aluminium and Young’s modulus for steel is Y
A steel wire is rigidly fixed along diameter of aluminium ring of radius R as shown. Linear expansion coefficient of steel is half of linear expansion coefficient for aluminium, then the thermal stress developed in steel wire is: (aAl is linear expansion coefficient for aluminium and Young’s modulus for steel is Y
Physics-General
Physics-
Figure shows isosceles triangle frame ABC of two different material shown in figure. Thermal expansion cofficient of the rod ADB is a1 and for rod ACB is a2 . End C is fixed and whole system is placed on smooth horizontal surface and D is midpoint of rod AB and CD is perpendicular to the AB. If temperature of the system is increase such as it is found that distance CD remain fixed the
Figure shows isosceles triangle frame ABC of two different material shown in figure. Thermal expansion cofficient of the rod ADB is a1 and for rod ACB is a2 . End C is fixed and whole system is placed on smooth horizontal surface and D is midpoint of rod AB and CD is perpendicular to the AB. If temperature of the system is increase such as it is found that distance CD remain fixed the
Physics-General
Physics-
A wire is bent in a parabolic shape followed by equation x = 4y2 . Consider origin as vertex of parabola. A wire parallel to y axis moves with constant speed 4 m/s along x-axis in the plane of bent wire. Then the acceleration of touching point of straight wire and parabolic wire is (when straight wire has x coordinate = 4 m) :
A wire is bent in a parabolic shape followed by equation x = 4y2 . Consider origin as vertex of parabola. A wire parallel to y axis moves with constant speed 4 m/s along x-axis in the plane of bent wire. Then the acceleration of touching point of straight wire and parabolic wire is (when straight wire has x coordinate = 4 m) :
Physics-General
Physics-
All the rods have same conductance ‘K’ and same area of cross section ‘A’. If ends A and C are maintained at temperature 2T0 and T0 respectively then which of the following is/are correct:
All the rods have same conductance ‘K’ and same area of cross section ‘A’. If ends A and C are maintained at temperature 2T0 and T0 respectively then which of the following is/are correct:
Physics-General
Physics-
Two large non conducting plates having surface charge densities + s and –s respectively, are fixed d distance apart. A small test charge q of mass m is attached to two non conducting springs each of spring constant k as shown in the figure. The sum of lengths of both springs in undeformed state is d. The charge q is released from rest with both the springs nondeformed. Then charge q will (neglect gravity)
Two large non conducting plates having surface charge densities + s and –s respectively, are fixed d distance apart. A small test charge q of mass m is attached to two non conducting springs each of spring constant k as shown in the figure. The sum of lengths of both springs in undeformed state is d. The charge q is released from rest with both the springs nondeformed. Then charge q will (neglect gravity)
Physics-General
