ZSM-5
Previous Years' Questions
GATE • CSIR-NET • IIT-JAM • ONGC • IOCL • BARC • HPCL • ISRO • UPSC-IFS • State PSCs (2017–2025)
GATE Chemistry 2024
The zeolite catalyst used in the Methanol-to-Gasoline (MTG) process is
Correct Answer: (B) ZSM-5
GATE Chemistry 2023
The IZA framework code for ZSM-5 is
Correct Answer: (B) MFI
GATE Chemical Engineering 2023
ZSM-5 is added to FCC catalyst primarily to
Correct Answer: (B) Increase gasoline octane number
CSIR-NET Chemical Sciences Dec 2023
The organic structure-directing agent (template) commonly used for synthesis of ZSM-5 is
Correct Answer: (C) Tetrapropylammonium (TPA⁺)
CSIR-NET Chemical Sciences June 2022
ZSM-5 is a ----- pore zeolite.
Correct Answer: (B) Medium
CSIR-NET 2021
Silicalite-1 is the aluminium-free analogue of
Correct Answer: (C) ZSM-5
IIT-JAM Chemistry 2024
The crystal system of ZSM-5 zeolite is
Correct Answer: (C) Orthorhombic
ONGC GT Chemistry 2024
Mobil’s catalytic dewaxing process using ZSM-5 is commercially known as
Correct Answer: (B) MDDW (Mobil Distillate Dewaxing)
IOCL Refining 2023
In aromatic complexes, ZSM-5 based catalysts are used for selective production of
Correct Answer: (C) para-xylene
UPHESC Assistant Professor 2025
Zeolite ZSM-5 is used in the manufacture of which of the following compounds ?
GATE Chemistry 2020
The protonic form of ZSM-5 used as acid catalyst is denoted as
Correct Answer: (B) H-ZSM-5
CSIR-NET June 2019
Shape selective catalysis leading to high para-selectivity in xylene isomerisation is shown by
Correct Answer: (C) ZSM-5
GATE Chemical 2018
The world’s first commercial Methanol-to-Gasoline (MTG) plant using ZSM-5 was commissioned in
Correct Answer: (C) New Zealand
HPCL Engineer 2022
Commercial production of ε-caprolactam (nylon-6 monomer) uses ZSM-5 in which reaction?
Correct Answer: (B) Vapour phase Beckmann rearrangement
BARC 2023
The pore opening of ZSM-5 consists of
Correct Answer: (B) 10-membered ring
ISRO SC Chemistry 2022
The “hydrocarbon pool” mechanism is associated with
Correct Answer: (B) Methanol-to-hydrocarbons over ZSM-5
GATE Chemistry 2025 (Memory-based)
The shape selectivity exhibited by ZSM-5 in aromatization reactions is primarily due to
(A) Reactant selectivity (B) Product selectivity (C) Transition-state selectivity (D) All of these
Correct Answer: (D) All of these
GATE Chemistry 2024
The zeolite used in the commercial production of para-xylene with >95% selectivity is
(A) Zeolite Beta (B) ZSM-5 (C) Zeolite Y (D) SAPO-11
Correct Answer: (B) ZSM-5
CSIR-NET Dec 2024
The Si/Al ratio in typical commercial ZSM-5 lies in the range
(A) 1–5 (B) 5–10 (C) 10–100 (D) >100
Correct Answer: (C) 10–100
ONGC GT Chemistry 2025
The process that uses ZSM-5 for removal of normal paraffins from diesel is called
(A) Hydrocracking (B) Catalytic dewaxing (MDDW) (C) Isodewaxing (D) Hydroisomerization
Correct Answer: (B) Catalytic dewaxing (MDDW)
IOCL Refinery Officer 2024
In FCC units, ZSM-5 additive increases gasoline research octane number (RON) by
(A) Cracking heavy ends (B) Producing light olefins that alkylate into high-octane components (C) Reducing aromatics (D) Increasing iso-paraffins
Correct Answer: (B)
BARC OCES Chemistry 2024
The 3-dimensional channel system of ZSM-5 consists of
(A) Only straight channels (B) Only sinusoidal channels (C) Straight + sinusoidal 10-ring channels (D) 12-ring channels
Correct Answer: (C) Straight + sinusoidal 10-ring channels
IIT-JAM Chemistry 2023
Which one of the following is a pentasil zeolite?
(A) Erionite (B) Mordenite (C) ZSM-5 (D) Faujasite
Correct Answer: (C) ZSM-5
CSIR-NET June 2023
The first C–C bond formation step in methanol-to-hydrocarbons (MTH) over ZSM-5 is still debated, but the widely accepted mechanism is
(A) Carbene mechanism (B) Hydrocarbon pool mechanism (C) Oxonium ylide mechanism (D) Koch carbonylation
Correct Answer: (B) Hydrocarbon pool mechanism
HPCL Engineer 2024
The commercial name of the process using ZSM-5 for selective toluene disproportionation to benzene + p-xylene is
(A) Parex (B) MSTDP (C) Tatoray (D) Xylene-plus
Correct Answer: (B) MSTDP (Mobil Selective Toluene DisProportionation)
UPSC IFS Chemistry 2024
The zeolite catalyst used in Lurgi’s Methanol-to-Propylene (MTP) process is
(A) SAPO-34 (B) ZSM-5 (C) Zeolite-Y (D) Both (A) and (B)
Correct Answer: (B) ZSM-5
GATE Chemistry 2021
The pore diameter of ZSM-5 is closest to the kinetic diameter of
(A) n-Hexane (B) p-Xylene (C) 1,3,5-Trimethylbenzene (D) Triisopropylbenzene
Correct Answer: (B) p-Xylene
CSIR-NET Dec 2020
The Brønsted acid sites in H-ZSM-5 are generated by
(A) Extra-framework Al (B) Framework Al with charge-balancing proton (C) Silanol groups (D) Lewis acidic Al
Correct Answer: (B) Framework Al with charge-balancing proton
ONGC GT 2022
The year in which Mobil Oil patented ZSM-5 was
(A) 1967 (B) 1972 (C) 1975 (D) 1980
Correct Answer: (C) 1975 (invented 1972, patented 1975)
ISRO Scientist Chemistry 2023
Among the following, the zeolite with highest thermal stability is
(A) Zeolite A (B) Zeolite Y (C) ZSM-5 (D) MCM-41
Correct Answer: (C) ZSM-5 (stable up to ~1100 °C)
GATE Chemical 2019
The commercial MTG plant in New Zealand produced gasoline from
(A) Natural gas via methanol (B) Coal via methanol (C) Biomass (D) Petroleum
Correct Answer: (A) Natural gas via methanol
GATE Chemistry 2025
The number of T-atoms (Si/Al) in the unit cell of ideal ZSM-5 (Si/Al = ∞) is
(A) 96 (B) 92 (C) 100 (D) 88
Correct Answer: (A) 96
CSIR-NET Chemical Sciences June 2025
Among the following catalysts, the one used in Mobil’s M2-forming process for aromatization of light naphtha is
(A) Pt/Re on Al₂O₃ (B) Pt on KL zeolite (C) Ga-modified ZSM-5 (D) Cr on Al₂O₃
Correct Answer: (C) Ga-modified ZSM-5
ONGC GT Chemistry 2024
The space group of high-silica ZSM-5 is
(A) Fm-3m (B) Pnma (C) I4/mmm (D) P6₃/mmc
Correct Answer: (B) Pnma (orthorhombic)
IOCL Refinery Officer 2025
In modern FCC units, ZSM-5 additive can increase propylene yield up to
(A) 2–4 wt% (B) 6–10 wt% (C) 12–18 wt% (D) >20 wt%
Correct Answer: (C) 12–18 wt%
BARC OCES 2024
The kinetic diameter of p-xylene (Å) is approximately
(A) 4.3 (B) 5.8 (C) 6.7 (D) 7.4
Correct Answer: (B) 5.8 Å (matches ZSM-5 pore ~5.5 Å)
IIT-JAM Chemistry 2025
Which of the following reactions does NOT occur inside ZSM-5 pores due to transition-state shape selectivity?
(A) Toluene + methanol → p-xylene (B) Formation of 1,3,5-triisopropylbenzene (C) Xylene isomerization (D) Ethylbenzene dealkylation
Correct Answer: (B) Formation of 1,3,5-triisopropylbenzene
CSIR-NET Dec 2022
The term “pentasil” refers to
(A) Five Si atoms in ring (B) Chains of five SiO₄ tetrahedra forming structural subunit (C) Five Al atoms (D) Zeolite with five pores
Correct Answer: (B) Chains of five SiO₄ tetrahedra
HPCL Engineer 2023
The commercial process that converts methanol to propylene using ZSM-5 is known as
(A) MTO (B) MTP (C) MTG (D) MOGD
Correct Answer: (B) MTP (Methanol-to-Propylene)
UPSC Geologist 2024
The zeolite ZSM-5 was discovered by scientists of which company?
(A) Union Carbide (B) Mobil Oil (C) BASF (D) UOP
Correct Answer: (B) Mobil Oil
GATE Chemistry 2017
The number of 10-membered ring channels per unit cell running along a- and b-axis in ZSM-5 is
(A) 2 straight + 2 sinusoidal (B) 4 straight + 4 sinusoidal (C) 8 total (D) 12 total
Correct Answer: (B) 4 straight + 4 sinusoidal