UPMSP · High School · 2024 – 2026
UP Board Class 10 Science
Previous Year Questions with Solutions — Chapter-wise
Built by reading all 22 official UPMSP question papers of 2024, 2025 and 2026 — every set of every year.
195 solved questions · 13 chapters · 15 in each · repeated questions carry a 9× chip showing how many of the 22 papers they appeared in
Chapter 1 · ChemistryChemical Reactions and Equations
15 solved questions
Write the balanced chemical equation for the following reactions:
- (i) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water
- (ii) Zinc + Silver nitrate → Zinc nitrate + Silver
- (iii) Nitrogen + Hydrogen → Ammonia
- (iv) Barium chloride + Sodium sulphate → Barium sulphate + Sodium chloride
(i)
Ca(OH)2 + CO2 → CaCO3↓ + H2OThis is the lime water test — the white precipitate of calcium carbonate turns the lime water milky.
(ii)
Zn + 2AgNO3 → Zn(NO3)2 + 2AgA displacement reaction. Zinc is more reactive than silver, so it displaces silver from its salt.
(iii)
N2 + 3H2 → 2NH3A combination reaction — the industrial Haber process.
(iv)
BaCl2 + Na2SO4 → BaSO4↓ + 2NaClA double displacement (precipitation) reaction. The white insoluble precipitate is barium sulphate.
Balance in this order: first the metal, then the non-metal, then hydrogen, and oxygen last. Never change a formula to balance an equation — only the coefficients in front of it.
What happens when zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas? Write only the balanced chemical equation.
This is a displacement reaction. Zinc is more reactive than hydrogen, so it displaces hydrogen from the acid.
What you observe: the zinc granules dissolve gradually, colourless bubbles of gas are given off, and the test tube becomes warm — the reaction is exothermic.
Test for the gas: bring a burning splint near the mouth of the tube. The gas burns with a pop sound, confirming hydrogen.
The given chemical equation is an example of which type of chemical reaction?
CuO + H2 → Cu + H2O- (A) Displacement reaction
- (B) Addition reaction
- (C) Redox reaction
- (D) Decomposition reaction
(C) Redox reaction
Both oxidation and reduction are happening together here:
| Substance | What happens | Name |
|---|---|---|
| CuO → Cu | Loses oxygen | Reduced — CuO is the oxidising agent |
| H2 → H2O | Gains oxygen | Oxidised — H2 is the reducing agent |
A reaction in which oxidation and reduction occur simultaneously is called a redox reaction.
It is technically a displacement too, but redox is the more complete answer because it describes what is happening to both substances.
Explain corrosion. Write its two examples and two methods for preventing it.
Corrosion is the slow eating away of the surface of a metal by the action of air, moisture or chemicals present around it.
Two examples:
- Rusting of iron — a reddish-brown layer of hydrated iron oxide forms on the surface. 4Fe + 3O2 + xH2O → 2Fe2O3·xH2O
- Copper turning green — copper reacts with moist carbon dioxide in air to form a green coating of basic copper carbonate.
Two methods of prevention:
- Painting, greasing or oiling — this puts a barrier between the metal and the air and moisture.
- Galvanisation — coating iron with a layer of zinc, which corrodes in preference to the iron.
(Other methods: electroplating with chromium or nickel, and alloying — iron is mixed with chromium and nickel to make stainless steel, which does not rust at all.)
Rusting needs both air and water together. Iron does not rust in dry air, nor in water that has no dissolved oxygen — which is why the experiment with three test tubes is always asked alongside.
What are exothermic and endothermic reactions? Explain with examples.
| Exothermic reaction | Endothermic reaction | |
|---|---|---|
| Meaning | Heat is released along with the products | Heat is absorbed from the surroundings |
| Surroundings | Become warm | Become cold |
| Energy of products | Less than that of reactants | More than that of reactants |
Exothermic examples:
CaO + H2O → Ca(OH)2 + heat CH4 + 2O2 → CO2 + 2H2O + heatRespiration in our body is also exothermic — glucose is broken down and energy is released. The decomposition of vegetable matter into compost is another everyday example.
Endothermic examples:
CaCO3 ⟶heat CaO + CO2 2AgCl ⟶sunlight 2Ag + Cl2Photosynthesis is endothermic too — plants absorb energy from sunlight.
Write the chemical equations for two decomposition reactions. Also write the reaction for the thermal decomposition of lead nitrate and state the colour of the gas evolved.
In a decomposition reaction a single compound breaks down into two or more simpler substances.
(i) Thermal decomposition — brought about by heat:
2FeSO4 ⟶heat Fe2O3 + SO2 + SO3(ii) Electrolytic decomposition — brought about by electricity:
2H2O ⟶electricity 2H2 + O2Thermal decomposition of lead nitrate:
2Pb(NO3)2 ⟶heat 2PbO + 4NO2 + O2The gas evolved is nitrogen dioxide (NO2), which is brown in colour. The residue left behind is yellow lead oxide.
A decomposition reaction is the opposite of a combination reaction, and it is almost always endothermic — energy has to be supplied to break the compound apart.
Which of the following pairs gives a displacement reaction?
- (A) NaCl solution and Copper metal
- (B) MgCl2 solution and Aluminium metal
- (C) FeSO4 solution and Silver metal
- (D) AgNO3 solution and Copper metal
(D) AgNO3 solution and Copper metal
Cu + 2AgNO3 → Cu(NO3)2 + 2AgA displacement reaction happens only when the free metal is more reactive than the metal in the salt. Copper is above silver in the reactivity series, so it displaces silver.
Why the others fail:
| Pair | Reason |
|---|---|
| NaCl + Cu | Sodium is far more reactive than copper |
| MgCl2 + Al | Magnesium is more reactive than aluminium |
| FeSO4 + Ag | Silver is less reactive than iron |
What you observe in (D): the blue-green colour of copper nitrate develops in the solution, and a shiny greyish-white deposit of silver collects on the copper.
Explain a precipitation reaction with an example.
A reaction in which an insoluble solid is formed when two solutions are mixed is called a precipitation reaction. The insoluble solid is the precipitate.
Example:
Na2SO4 + BaCl2 → BaSO4↓ + 2NaClOn mixing the two colourless solutions, a white precipitate of barium sulphate appears at once.
Another example:
Pb(NO3)2 + 2KI → PbI2↓ + 2KNO3Here the precipitate of lead iodide is bright yellow.
Every precipitation reaction is also a double displacement reaction, because the two compounds exchange their ions.
The downward arrow ↓ after a formula marks a precipitate, and an upward arrow ↑ marks a gas. Adding these gets you marks in the board exam.
Select the oxidising and reducing agents with reasons in the following reaction:
MnO2 + 4HCl → MnCl2 + 2H2O + Cl2| Substance | What happens to it | It is | Its role |
|---|---|---|---|
| MnO2 | Loses oxygen to become MnCl2 | Reduced | Oxidising agent |
| HCl | Loses hydrogen to become Cl2 | Oxidised | Reducing agent |
How to decide, in one line each:
- The substance that is reduced is the oxidising agent — it gave its oxygen away to somebody else.
- The substance that is oxidised is the reducing agent — it took the oxygen, so it must have reduced the other one.
Definitions to quote:
- Oxidation — gain of oxygen or loss of hydrogen.
- Reduction — loss of oxygen or gain of hydrogen.
The agent is always the opposite of what happens to it. Students routinely lose this mark by writing that the oxidised substance is the oxidising agent.
Which of the following is the balanced equation for the reaction of iron with steam?
- (A) Fe + H2O → FeO + H2
- (B) 3Fe + 4H2O → Fe3O4 + 4H2
- (C) 2Fe + 3H2O → Fe2O3 + 3H2
- (D) Fe + 2H2O → Fe(OH)2 + H2
(B)
3Fe + 4H2O ⟶steam Fe3O4 + 4H2Check the balance:
| Atom | Left | Right |
|---|---|---|
| Fe | 3 | 3 |
| H | 4 × 2 = 8 | 4 × 2 = 8 |
| O | 4 | 4 |
Iron does not react with cold water, and only very slowly with hot water, but it reacts readily with steam. The product is the black oxide Fe3O4, not Fe2O3.
Explain combination and displacement reactions with one example each.
Combination reaction: two or more substances combine to form a single new substance.
CaO + H2O → Ca(OH)2Quick lime reacts vigorously with water to give slaked lime, releasing a large amount of heat. So this is also an exothermic reaction.
Another example is the burning of magnesium ribbon:
2Mg + O2 ⟶burn 2MgODisplacement reaction: a more reactive element displaces a less reactive element from its compound.
Fe + CuSO4 → FeSO4 + CuWhen an iron nail is dipped into blue copper sulphate solution, the blue colour fades to pale green and a brownish-red deposit of copper forms on the nail. Iron is more reactive than copper, so it takes its place.
Plaster of Paris is prepared by heating gypsum. What type of change is this?
- (A) Exothermic chemical reaction
- (B) Exothermic physical change
- (C) Reversible endothermic reaction
- (D) Irreversible endothermic reaction
(C) Reversible endothermic reaction
CaSO4·2H2O ⟶373 K CaSO4·12H2O + 112H2O- It is endothermic because heat has to be supplied to drive off the water.
- It is reversible because adding water back to Plaster of Paris turns it into a hard solid mass of gypsum again — which is exactly how it sets a broken bone in place.
Gypsum must be heated carefully to 373 K (100°C) only. Above that, all the water is driven off and the substance formed will not set properly.
What is rancidity? Write two methods to prevent it.
Rancidity is the process in which fats and oils in food get oxidised on standing in air, so that the food develops an unpleasant smell and taste.
Two methods of prevention:
- Adding antioxidants to the food. These get oxidised in place of the fats and delay rancidity.
- Packing the food in an atmosphere of nitrogen — an unreactive gas — so that no oxygen is present. This is why packets of chips are filled with nitrogen.
(Other methods: storing in airtight containers, keeping food refrigerated, and keeping it away from sunlight.)
Rancidity is an oxidation process, so every method of preventing it works by keeping oxygen away from the fat or by slowing the reaction down.
Balance the following chemical equations:
- (i) Fe + H2O → Fe3O4 + H2
- (ii) Al + CuCl2 → AlCl3 + Cu
- (iii) NaOH + H2SO4 → Na2SO4 + H2O
(i)
3Fe + 4H2O → Fe3O4 + 4H2(ii)
2Al + 3CuCl2 → 2AlCl3 + 3Cu(iii)
2NaOH + H2SO4 → Na2SO4 + 2H2OThe method — hit and trial:
- Write down the number of atoms of each element on both sides.
- Balance the element with the largest number of atoms first, then work through the rest.
- Balance hydrogen and oxygen last, since they appear in the most places.
- Check every element once more at the end.
Only the coefficients in front of a formula may be changed. Changing a subscript — writing H2O2 in place of H2O — changes the substance itself and is always wrong.
Which type of reaction is represented by the following equation?
AgNO3 + NaCl → AgCl↓ + NaNO3- (A) Combination reaction
- (B) Decomposition reaction
- (C) Double displacement reaction
- (D) Displacement reaction
(C) Double displacement reaction
Here two compounds exchange their ions with each other. The silver joins the chloride, and the sodium joins the nitrate:
| Before | After |
|---|---|
| Ag — NO3 | Ag — Cl (white precipitate) |
| Na — Cl | Na — NO3 |
Since an insoluble white precipitate of silver chloride is formed, it is also a precipitation reaction.
Tell the two apart by counting: in a displacement reaction one element pushes another out; in a double displacement reaction two compounds swap partners. If both reactants are compounds, it is double displacement.
Chapter 2 · ChemistryAcids, Bases and Salts
15 solved questions
Write the chemical reaction for the manufacture of bleaching powder and its two applications.
Manufacture: bleaching powder is produced by the action of chlorine on dry slaked lime.
Ca(OH)2 + Cl2 → CaOCl2 + H2OThe formula of bleaching powder is CaOCl2 (calcium oxychloride).
Two applications:
- For bleaching cotton and linen in the textile industry, and wood pulp in the paper industry.
- For disinfecting drinking water, to make it free of germs.
(Also used as an oxidising agent in chemical industries.)
A solution turns red litmus blue. The possible pH value of this solution is:
- (A) 1
- (B) 4
- (C) 7
- (D) 10
(D) 10
Red litmus turns blue only in a basic solution, and a base has a pH greater than 7. Of the options, only 10 qualifies.
| pH | Nature | Effect on litmus |
|---|---|---|
| Less than 7 | Acidic | Turns blue litmus red |
| Exactly 7 | Neutral | No change |
| More than 7 | Basic | Turns red litmus blue |
A memory hook: Base turns red to Blue. And the lower the pH, the stronger the acid.
What type of salt is NaHCO3?
- (A) Acidic salt
- (B) Basic salt
- (C) Neutral salt
- (D) Double salt
(B) Basic salt
Sodium hydrogencarbonate (baking soda) is formed from a strong base, NaOH, and a weak acid, H2CO3. A salt of a strong base and a weak acid is basic, with a pH above 7 (about 8.3).
| Salt | From | Nature |
|---|---|---|
| NaCl | Strong base + strong acid | Neutral (pH 7) |
| NaHCO3, Na2CO3 | Strong base + weak acid | Basic |
| NH4Cl | Weak base + strong acid | Acidic |
Its basic nature is why baking soda is used as an antacid — it neutralises the excess acid in the stomach.
Write the definitions of acid and base, and explain a neutralisation reaction with an example.
Acid: a substance that gives hydrogen ions (H+) in aqueous solution. Acids taste sour and turn blue litmus…