SSC (Marathi Semi-English) १० वीं कक्षा - Maharashtra State Board Important Questions for Science and Technology 1

CuSO_4(aq) + Zn_(s) → ZnSO_4(aq) + Cu_(s) is an example of a decomposition reaction.

The reddish brown deposit formed on iron nails kept in a solution of copper sulphate is

1. Cu₂O
2. Cu
3. CuO
4. CuS

Methyl orange is used as an indicator. It shows colour change in acid, base and neutral substance. Tabulate your result as follows:

The chemical formula for rust is.............. .

When the substance ‘A’ is added to a solution of BaSO₄, a yellow precipitate is formed.

1. What do you think substance A is likely to be?
2. Name the precipitate.
3. Which type of reaction is this?

Taking into consideration the relationship in the first pair, complete the second pair

2H₂ + O₂ → 2H₂O :Combination Reaction :: 2HgO → 2Hg + O₂:_________

Find the odd man out:

Turmeric, Methyl Orange, Rose petals, Beetroot.

Rewrite the following statements by selecting the correct options:
\[\ce{CaCO3 ->[\Delta] CaO + CO2 ^}\] is a __________ reaction.

What is meant by rust?

Write the chemical formula of rust.

Give a scientific reason.

When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky.

Give scientific reason.

It is reccommended to use air tight container for storing oil for long time.

Observe the following picture a write down the chemical reaction with the explanation.

Identify from the reaction the reactants that undergo oxidation and reduction.
Fe + S → FeS

Write scientific reasons.

Lemon or tamarind is used for cleaning copper vessels turned greenish.

Identify the type of following reaction :

Write down what you understood from the following chemical reaction.

AgNO_3(aq) + NaCI_(aq) → AgCI ↓ + NaNO_3(aq)

Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
 Reaction on anode region :

`F_e(s) → Fe^(2+) (aq) +2e^-`

 Reaction on anode region :

`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `

When Fe²⁺ ions migrate from anode region they react with ................... to form Fe³⁺ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.

`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `

A way to prevent rusting ..................................................................

i) Observe the following reaction and answer the following questions.
`CuSO_4 (aq) + Fe (s) →  FeSO_4(aq) + Cu (s)`
a) Identify and write the type of chemical reaction.
b) Write the definition of above reaction.

Identify the process shown in the diagram and explain it in short