Answer:
a. The student performed the splint test incorrectly. He should of observed a popping sound when the splint was placed in the test tube.
Explanation:
It is given that a student performed an experiment where he dropped a nickel metal in to HCl solution. He observed the reaction and performed a splint test in the test tube that is filled with a gas which is formed while Nickle is dropped into the solution of HCl.
But the experiment that the student performed was incorrect. He must have observed the popping sound when the splint was placed in the test tube.
When the splint was added to the gas splint flared up. The hydrogen gas pops out when exposed to the flame.

Thus the correct option is (a).
Answer:
35 . 29%
Explanation:
no. of questions in test =34
no. of questions answered correctly =22
therefore, no. of questions answered incorrectly =34 - 22
=12
error percentage = 12/34 * 100
=35 .29 %
Answer:
Explanation:
Heat required to convert ice to ice at 0⁰C
= mass x specific heat x rise in temperature
= 18 x 2.09 x 20
= 752.4 J .
heat required to convert ice at 0⁰C to water at 0⁰C
mass x latent heat of fusion
= 18 x 336
= 6048 J
Heat required to increase the temperature of water to 100⁰C
= 18 x 4.2 x 100
= 7560 J
Total heat required
7560 + 6048 + 752.4
= 14360.4 J
ionic bond:
Bond formed when an atom donates its electron and other atom receives those electrons.
polar covalent:
Bond formed by equal sharing of electrons between both the atoms and there is an electronegativity difference between the two atoms.
Nonpolar covalent:
Bond formed by equal sharing of electrons between both the atoms and there is no electronegativity difference between the two atoms.
Metallic:
Formed between two metals.
So the bond between :
Phosphorus and chlorine-polar covalent bond as it is formed by equal sharing of electrons between both the atoms and there is an electronegativity difference between the two atoms.
Potassium and oxygen -ionic bond as here potassium donates its electron and oxygen receives those electrons
Fluorine and fluorine -Non polar covalent bond as formed by equal sharing of electrons between both the atoms and there is no electronegativity difference between the two atoms.
Copper and aluminum-metallic bond as Formed between two metals.
Carbon and fluorine -polar covalent bond as it is formed by equal sharing of electrons between both the atoms and there is an electronegativity difference between the two atoms.
Carbon and hydrogen --Non polar covalent bond as formed by equal sharing of electrons between both the atoms and there is no electronegativity difference between the two atoms.
Aluminum and oxygen--ionic bond as here aluminum donates its electron and oxygen receives those electrons
Silver and copper --metallic bond as Formed between two metals.
Benzene is used for pesticides and detergents. It is also used for other things besides these.