if any one have their previous pre board question paper of science of class 10 cbse plz help me tomorrow is my exam
Answers
1.
A Mendelian experiment consisted of breeding pea plants bearing violet flowers with
pea plants bearing white flowers. What will be the result in F1
progeny ?
Write the energy conversion that takes place in a hydropower plant.
3
A compound ‘X’ on heating with excess conc. sulphuric acid at 443 K gives an
unsaturated compound ‘Y’. ‘X’ also reacts with sodium metal to evolve a colourless
gas ‘Z’. Identify ‘X’, ‘Y’ and ‘Z’. Write the equation of the chemical reaction of
formation of ‘Y’ and also write the role of sulphuric acid in the reaction.
4
(a) Name one gustatory receptor and one olfactory receptor present in human beings.
(b) Write a and b in the given flow chart of neuron through which information
travels as an electrical impulse.
Dendrite a b End point of Neuron
31/1 4
5
If the image formed by a spherical mirror for all positions of the object placed in front
of it is always erect and diminished, what type of mirror is it ? Draw a labelled ray
diagram to support your answer.
6. Decomposition reactions require energy either in the form of heat or light or electricity
for breaking down the reactants. Write one equation each for decomposition reactions
where energy is supplied in the form of heat, light and electricity.
7.2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal
taken in a test tube. When the contents are warmed, a gas evolves which is bubbled
through a soap solution before testing. Write the equation of the chemical reaction
involved and the test to detect the gas. Name the gas which will be evolved when the
same metal reacts with dilute solution of a strong acid.
OR
The pH of a salt used to make tasty and crispy pakoras is 14. Identify the salt and
write a chemical equation for its formation. List its two uses.