Tests for Hydrogen

Q.

Why curdling of milk is a chemical change?

Q.

The properties of a compound are same as that of its constituent elements.

1. True

2. False

Q.

Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.

1. Process – A is a chemical change

2. Process – B is a chemical change

3. Both processes A and B are chemical changes

4. None of these processes is a chemical change

Q.

The questions below consist of Assertion (A) and Reason (R). Use the following key to select the correct answer:

(a) If both assertion and reason are correct and the reason is the correct explanation for the assertion.

(b) If both assertion and reason are correct but the reason is not the correct explanation for the assertion.

(c) If the assertion is correct but the reason is incorrect.

(d) If the assertion is incorrect but the reason is correct.

Assertion: A chemical change cannot be easily reversed.

Reason: A new chemical substance is formed as a result of chemical change.

1. (a)

2. (b)

3. (c)

4. (d)

Q.

A change is said to be a chemical change when-

1. new substances are formed

2. energy changes occur

3. the change cannot be easily reversed

4. all statements are correct

Q. Hydrogen and oxygen when burnt together give a flame known as __________ flame.

1. sodium hydroxide
2. hydrogen sulphide
3. water gas
4. oxy-hydrogen

Q.

The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction is ___

$(Fe/Mg/Pb/Al)$

Q.

. Ripening of fruits

Q.

Which of the following is known as water producing gas?

1. Hydrogen

2. Helium

3. None of these

4. Nitrogen

Q.

Hydrogen gas burns with a _____ flame and pop sound.

Q.

Hydrogen forms an ___________ mixture with air.

Q.

How would you show that setting of a curd is a chemical change?

Q.

The properties of a compound are same as that of its constituent elements.

1. True

2. False

Q.

Which hydride is not a reducing agent among the following?

1. ${\mathrm{H}}_2\mathrm{Se}$

2. ${\mathrm{H}}_2\mathrm{O}$

3. ${\mathrm{H}}_2\mathrm{Te}$

4. ${\mathrm{H}}_2\mathrm{S}$

Q. Hydride ion $\left(H^{-}\right)$ is a stronger base than hydroxide ion $\left(O{H}^{-}\right)$. In the light of the above fact, which of the following reactions will take place if $NaH$ is dissolved in water?

1. $H_{\left(aq\right)}^{-}+H_{2}O\to H_3{O}_{\left(aq\right)}^{+}$
2. $H_{\left(aq\right)}^{-}+H_{2}O\to O{H}^{-}+H_2$
3. $H_{\left(aq\right)}^{-}+H_{2}O\to H_3{O}^{-}$
4. $H_{\left(aq\right)}^{-}+H_{2}O\to$ No reaction

Q.

List any four uses of hydrogen gas.

Q.

Which of the following changes is not a chemical change?

1. Burning sodium in the atmosphere of chlorine

2. Dropping sodium into water

3. Cutting sodium piece with the knife

4. Dropping sodium into a solution of sodium chloride in water​

Q.

Write the characteristic of chemical change.

Q. Which amongst the following is a test to detect hydrogen gas?​

Q. Presence of water can be detected by:

1. adding a drop to anhydrous copper suphate which changes its colour from white to blue
2. by boiling and testing for the presence of $H_2$ and $O_2$
3. by checking the production of lather when mixed with soap
4. by seeing its colour and transparency

Q. Can we think of hydrogen as a future fuel? Justify your answer.

Q. What happens when hydrogen burns in air?

Q. Give equation to show the reaction of hydrogen with (a) Na, (b) Ca (c) CO, (d) N, (e) S, (f) Cl (g) CuO.

Q. Hydrogen turns blue litmus paper to _______.

1. red
2. blue
3. pink
4. no effect

Q.

What does it mean to be fully ionized?

Q. Which of the following will not displace hydrogen?

1. Ba
2. Sn
3. Pb
4. Hg

Q. The product formed when hydrogen is burnt in air is:

1. hydrogen peroxide
2. ozone
3. water
4. hydronium

Q.

State what do you observe when a piece of moist red litmus paper is placed in a gas jar containing ammonia.

Q. A metal oxide that is reduced by hydrogen is:

1. $A{l}_2{O}_3$
2. $CuO$
3. $CaO$
4. $N{a}_{2}O$

Q. Give examples of six proton solvents other than water, and show how they self ionize.